Search Results for: nematocysts

Nematocysts

tentacles

When people think of jellyfish, the first thing that comes to mind is usually something about their sting. This capability is characteristic of most jellies and their relatives in the phylum Cnidaria. The name of the group is actually derived from their possession of structures known as cnidae. Each is located within a specialized cell that houses the cnida, which is a capsule with an attached hollow thread. Nematocyst is the more familiar term applied to specialized cnidae that are characteristic of scyphozoan and other types of jellies, and other cnidarians.

Imagine trying to capture live prey without the aid of teeth, a jaw and hard protective body parts. What if your body also consisted of delicate gelatinous tissue that would easily be destroyed by a struggling prey. That’s the challenge that jellies face every time they attempt to feed. Nematocysts come handily to the rescue. Rather than being designed for attacking people, stinging nematocysts function primarily for the capture of prey, and secondarily as a defense mechanism. A wide variety of nematocysts have been classified.  Many function to inject toxins to immobilize prey, while others serve to entangle and hold onto the intended meal by wrapping around it.

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An undischarged nematocyst is housed within a cell known as a nematocyte. Most nematocytes are located on the tentacles of the jelly, which are the primary food capturing part of the body. Scyphozoan jellies also concentrate them around the mouth and on the gastric filaments of the stomach. The nematocyst capsule within the nematocyte is covered by a trapdoor-like operculum. Inside the capsule is the long, cylindrical tubule of the nematocyst. At the base of the tubule is an enlarged area known as the shaft. Both the shaft and the tubule may be endowed with an impressive set of spines (at least when viewed with scanning electron microscopy!). Characteristics of the tubule, spines and shaft are used in classifying the bewildering array of nematocyst types. You may see terms such as heterotrichous (tubule spines of unequal size), homotrichous (spines of equal size), atrichous (tubule without spines), eurytele (shaft dilated at its far end), haploneme (tubule without a well-defined shaft), heteroneme (tubule with a well-defined shaft), and isorhiza (tubule diameter the same throughout). Obviously there were some dedicated early researchers who didn’t have much of a social life! Species of cnidarian jellies vary in the types of nematocysts they possess, and this can be used to some extent in classifying and identification. A common nematocyst style among scyphozoan jellies is the heterotrichous microbasic eurytele (say that fast 3 times), one in which the shaft is relatively short and has a widened portion at the far (distal) end, with the spines largest near the shaft.

Nematocysts are continuously produced within cells known as nematoblasts. Since they are not reused following discharge and it is energetically costly to produce them, it’s to the advantage of the jelly to fire only when necessary. Both mechanical (touch) and chemical stimuli may act to trigger nematocyst firing. Contact with members of their own species generally doesn’t result in firing, which makes sense when you see a dense swarm of sea nettles that are frequently touching. When a potential prey item, such as a larval fish or another type of jelly makes contact, the result is quite different. Discharge is initiated by the opening of the capsule operculum. Immediately the tubule begins to evert out with a twisting motion. Although not completely understood, discharge appears to involve an increase of osmotic pressure within the capsule and perhaps a release of tension within the capsule wall. Combined with the spines, the twisting acts to drill the tubule into the unfortunate victim. The tubule then separates from the capsule and remains imbedded in the flesh.

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Within a fraction of a second, hundreds or even thousands of nematocysts discharge with sufficient force to penetrate the skin or exoskeleton of the prey.  Nematocysts can discharge independently of each other in certain cases, or be influenced by interactions with surrounding cells or even the simple nerve net system. They can discharge even after the jellyfish has been dead for hours or days, much to the chagrin of beachgoers with a penchant for fondling beached gelatinous blobs.

See nematocyst discharge in action, from the Pacific Cnidaria Research Institute: box jelly nematocysts

Nematocysts inject a complex slew of chemical agents into their prey or human victim. The numerous spines help to anchor the tubule into the prey and also serve as sites for the discharge of the toxic brew. Toxins and other substances may have a direct deleterious effect, or cause an immune reaction. It’s not clear whether different nematocyst types have characteristic toxins. Different species of jellies do, however, vary greatly in the suite of toxins they inject. Those that specialize in preying on fish, such as the sea wasp (Chironex) or the Portuguese man-of-war (Physalia), will tend to have very potent toxins that quickly immobilize the prey (and hence are quite painful to humans). Jellies that favor more gelatinous fare, like the egg-yolk jelly (Phacellophora), don’t need to concentrate on subduing the prey. Instead they often have nematocysts that are quite sticky and good at holding slimy blobs. Others like the moon jelly (Aurelia) rely more on bell mucus to capture zooplankton and thus have a comparatively reduced reliance on nematocysts.

 

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Jellyfish toxins include a poorly understood array of complex chemicals, many of which are proteinaceous. Many have deleterious effects on cell membranes and cause them to rupture. This may, for example, lead to the breaking up of red blood cells, certainly not a desirable response to a sting. Other toxins have disruptive effects on the action of nerve and muscle cell membranes and impair their normal function. Throw in toxins that degrade collagen, break down proteins and lipids, and disrupt cellular influx of ions like calcium, and you can see why jellyfish mean business.

So behold the amazing nematocyst. Although small in stature, the combined efforts of multitudes of these microscopic workhorses is sufficient to subdue creatures that seemingly should have no problem against a delicate gelatinous blob. Nematocysts are one more reason to admire our gelatinous friends, and they are key to the success that jellyfish and their cnidarian relatives have had in conquering all marine habitats.

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Vallentinia

Vallentinia adherens  Hyman, 1947
Phylum Cnidaria / Class Hydrozoa / Order Limnomedusae / Family Olindiasidae
vallentinia

Unless you’re really determined, don’t try to find this tiny hydromedusae unless you have lots of time and know where to look. It’s only known from the waters off Pacific Grove in Monterey Bay, and lives quite inconspicuously attached to seaweeds in shallow nearshore habitats. The transparent bell only reaches a diameter of about 8 mm. Each of the 4 radial canals holds a ruffled golden-brown gonad. The central squarish stomach has a creamy white color. Four long tentacles, each with a terminal adhesive disc, and about 40 shorter tentacles, usually with a terminal disc, ring the bell margin. The rings of nematocysts on the tentacles are very distinctive. One or two statocysts lie between each of the tentacles.

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Liriope

Liriope tetraphylla (Chamisso & Eysenhardt, 1821)
Phylum Cnidaria / Class Hydrozoa / Order Trachymedusae / Family Geryoniidae
liriope

This tiny gelatinous jewel is a master of the fine art of transparency. Even when abundant near the surface, it’s difficult to know that they’re even there. If you do see them, identification of this trachymedusa is fairly easy. The transparent, colorless bell may be up to 3 cm diameter but is usually less. A long conical peduncle, to which is attached the stomach, extends from beneath the bell. Four radial canals continue along the length of the peduncle, and 4 flat gonads lie on the canals in the bell area. A total of 8 tentacles (4 long alternating with 4 short ones) are attached to the bell margin. Apparently the sting of the nematocysts can be mildly irritating, particularly if large numbers of individuals are involved.

Like other trachymedusae, this species lacks an attached polyp. Gonads release eggs or sperm into the water and the fertilized eggs develop into planulae. These form free-swimming actinula larvae, which develop directly into medusae. In nearshore waters of central and southern California, Liriope can occur in massive surface aggregations during periods of warmer oceanic water intrusion. This typically happens during fall months in Monterey Bay. This widespread species occurs worldwide from about 40 degrees N to 40 degrees S latitude, and ranges into northern California on the West Coast. It is a fairly common jelly in Mexico’s Sea of Cortez.

All images in the JelliesZone © David Wrobel and may not be copied or used in any form without permission.

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Haliscera

Haliscera conica Vanhoffen, 1902, top; H. bigelowi Kramp, 1947, bottom
Phylum Cnidaria / Class Hydrozoa / Order Trachymedusae / Family Halicreatidae
halisceraconi
haliscerabige

Both of these deep-water species are commonly collected in mid-water trawls. They are characterized by a bell width no more than 2.5 cm, and a rounded to conical apical projection (more pronounced in Haliscera conica). The mouth and stomach are circular, and connect to 8 broad radial canals. The canals are typically swollen in their midsection by flat. oval gonads. The velum is quite broad. About 160 tentacles (lost in these trawl collected specimens) line the bell margin. They have nematocysts concentrated in the distal (farthest) ends, and are about 1 to 3 times as long as the bell width. Both species are transparent and colorless, but may have an orange tinge to the canals and gonads, or rose-pink stomach and mouth (as seen in the photo of Haliscera bigelowi). They inhabit mid-water zones in both the Atlantic and Pacific Oceans.

All images in the JelliesZone © David Wrobel and may not be copied or used in any form without permission.

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Hitchhikers

Hitchhikers on Gelatinous Zooplankton

butterfish1

For creatures of the open sea realm, there are precious few protective sites. Many gelatinous animals serve as convenient traveling homes or resting places for a variety of other creatures. Certain types of larval fish and crustaceans are the primary users of this resource. Careful observation of gelatinous zooplankton will often reveal the presence of one or more hitchhikers.

Hitchhiking serves a number of purposes, including protection, a source of food, and distribution. Some larval or juvenile animals use their gelatinous host as a platform for development to adulthood. Other species may spend their entire lives on a jelly after settling down. Juvenile fishes, such as the medusafish (Icichthys lockingtoni), Pacific butterfish (Peprilus simillimus), and walleye pollock (Theragra chalcogramma) often lurk in the vicinity of large jellies. When danger approaches, they dive into the protective confines of the bell or among the tentacles. On the West Coast, purple-stripe jellies, sea nettles, moon jellies, lion’s mane and egg-yolk jellies frequently harbor piscine joyriders. Medusafish are even occasionally seen inside large salps. In some cases the relationship is commensal, in which case the jellyfish is not apparently effected by the association. Some fishes, however, may be ectoparasitic or even predatory on their host jelly. It’s not entirely clear how the fish avoid becoming a meal for the jellyfish. One possible mechanism is avoiding contact with the tentacles. It does seem hard to believe that a fish could somehow avoid touching the ever-moving tentacles while diving deep beneath the bell when danger approaches. Others include immunity to the nematocyst stings and production of mucus that reduces firing of nematocysts.

Crabs, such as the slender crab (Cancer gracilis), often associate with jellyfish before assuming a benthic existence. Pelagia colorata seem particularly favored by these crabs. Many hitchhikers grab food that the host has collected, but they may also consume host tissue. For this reason the association can be somewhat deleterious to the gelatinous host. An association that is certainly unfavorable to the host is that between the larval sea anemone, Peachia quinquecapitata, and certain hydromedusae.

phronima6
phronima1

A large number of amphipods in the family Hyperiidae are associated with many gelatinous animals. Medusae, siphonophores, ctenophores, pteropods and salps all serve as homes for these crustaceans. Often an amphipod will excavate a protective pit in the tissue of the host, or may be embedded deeper inside the animal. Females of one hyperiid amphipod, Phronima sedentaria, actually take over the tests of certain pelagic tunicates and swim while covered in their modified protective “barrel.” Phronima broods eggs within the barrel, and the hatchlings then consume their home before searching for more salp victims. This has to be one of the creepiest associations in the marine world! Certain salps are also used by males of the epipelagic octopus, Ocythoe tuberculata. The octopus uses jet propulsion to swim, even while inside its protective gelatinous home.

butterfish2
butterfish3

Juvenile fishes, such as the Pacific butterfish (Peprilus simillimus) seen in these two photos, often lurk in the vicinity of large jellies. When potential danger approaches, they dive into the protective confines of the bell or among the tentacles and oral arms. Somehow the fish manage to avoid the nasty sting of the ever-moving tentacles. Some jellies may harbor an entourage of a dozen or more fish. The silvery butterfish appear pretty conspicuous, but within an always moving jellyfish, the hitchhikers seemingly disappear in the mass of oral arms. Juvenile butterfish and other hitchhiking fish dine on zooplankton that the jelly has collected, and probably nibble on gelatinous tissue when captured prey are scarce. Eventually the fish decide that it’s time to strike off on their own, and they begin an independent adult existence. It’s not clear whether the jellyfish host benefits from this association, but the advantages to the hitchhiking fish seem apparent.

pelagiacrabs
slender crab-chrysaora

Crabs, such as the slender crabs seen here (Cancer gracilis), often spend their formative months in association with a jellyfish before assuming a benthic existence. Chrysaora colorata seem particularly favored by these crustaceans. It is not unusual to see an older, battle-worn Chrysaora with 50 or more tiny crabs hitching a ride. Unfortunately for the jelly, the relationship is not totally benign. The crabs dine on food that the jellyfish has labored to collect, and probably have no qualms about nibbling on delicate gelatinous flesh. They even can enter the stomach of the jelly without apparent harm. After drifting for many miles, the juvenile crabs somehow determine that the time is ripe to jump free and begin the perilous journey to the ocean bottom. These in turn produce the planktonic zoea larvae that seek out gelatinous traveling hosts.

barnacles

Pelagic barnacles (Family Lepadidae) will attach to just about anything floating in the open ocean. One species, Alepas pacifica, has taken things a step further and sets up shop on the bells of large jellies, such as egg-yolk jellies (seen here in the photo), purple-stripe jellies, and at least 5 other scyphozoan species. Typically the barnacles, which may occur singly or in clumps of up to 8 to 10 individuals, are attached at the top of the bell in the center. To lighten the load on their gelatinous host, the hard shell component characteristic of other barnacles is very thin and reduced. It’s hard to say whether the jelly is harmed by it’s crustacean hitchhikers, but once attached, there’s not much it can do. With certain scyphozoan species, it appears that the barnacles are parasitic, feeding on gonadal tissue of the jellyfish. Most large jellies however do seem to avoid the extra load – it’s relatively uncommon to see an egg-yolk jelly wearing a pelagic barnacle cap.

amphipods

A large number of crustaceans known as amphipods (mainly those in the Family Hyperiidae) are associated with gelatinous animals. Hyperiid amphipods often have species-specific relationships, such that a particular species of amphipod may be found only on one or perhaps several related species of gelatinous zooplankton. Medusae, siphonophores, ctenophores, pteropods and salps all serve as homes for these crustaceans. The unfortunate comb jelly in the photo here (Hormiphora) is burdened by over a dozen of the pesky hitchhikers. Often an amphipod will excavate a protective pit in the tissue of the host, or may be embedded deeper inside the animal. Some living amphipods can even be found inside the stomachs of hydromedusae. It’s not clear if these amphipods typically consume host tissue and what other harm they may present. With a load like the comb jelly pictured here, it would appear that there must be some disadvantage to hosting a throng of amphipods. If disturbed excessively, hyperiid amphipods will swim away from the host and seek another gelatinous home.

anemones

An association that is certainly unfavorable to the jellyfish host is that between the larval sea anemone, Peachia quinquecapitata, and certain hydromedusae including Mitrocoma and Clytia. Young planktonic anemone larvae are ingested by the jellyfish, and then feed on the gonads and stomach of their hapless host. Eventually the anemones (two are seen in this photo) drop off and assume a more typical benthic lifestyle as adults.

larvalfish

When you’re a juvenile fish, cast into the dangerous waters of the open ocean, predators are an ever-present threat. Everywhere, it would seem, there is someone seeking a tasty meal. With shelter at a precious premium, anything goes. That’s where large jellies, like the egg-yolk jelly (Phacellophora), can come in quite handy. In addition to providing a place to hide, the jelly’s stinging ability is probably an effective deterrent for many would be predators. Here a tiny juvenile fish finds comfortable accommodations among the tentacles and oral arms of an egg-yolk jelly. Eventually it will abandon its gelatinous host and assume an independent existence.

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Mollusc References

Listed here are a variety of scientific papers that relate to the study of gelatinous molluscs. These papers are published in scientific journals that are not available in public libraries – you will need access to a university library or online sources. Note that references with author names in color are links to abstracts (summaries) provided by several publishing companies that produce scientific journals. In most cases, the full journal papers are available online by paid subscription (check the home page of each publishing company for details).

To search for online literature, use the new Google tool below (About Google Scholar). Use any information available – author, topic, title, words that appear in title, etc. If you see a reference below that strikes your fancy, use that information for the search. Make your query as specific as possible to limit the number of search results. If you’re lucky, you’ll come up with a link to the complete research paper, or at least an abstract. This is a new service so don’t expect everything to be online, but with time it should improve.

Google Scholar


Bé, A.W.H. and R.W. Gilmer. 1977. A zoogeographic and taxonomic review of euthecosomatous pteropoda. Pp. 733-808 In: Oceanic Micropaleontology, Vol. 1. A.T.S. Ramsey (ed.). Academic Press, London.

Bertsch, H. 1969. A note on the range of Gastropteron pacificum. Veliger, 11:431-433.

Conover, R. J. and C. M. Lalli. 1972. Feeding and growth in Clione limacina (Phipps), a pteropod mollusc.
Journal of Experimental Marine Biology and Ecology, 9: 279–302.

Dadon, J.R. and S.F. Chauvin. 1998.  Distribution and abundance of (Gymnosomata Gastropoda:
Opisthobranchia) in the Southwest Atlantic.  Journal of Molluscan Studies, 64(3):345-354.

Dales, R.P. 1952. The distribution of some heteropod molluscs off the Pacific coast of North America. Proceedings of the Zoological Society of London, 122:1007-1015.

Davenport, J. and A. Bebbington. 1990. Observations on the swimming and buoyancy of some thecosomatous pteropod gastropods. Journal of Molluscan Studies, 56:487-497.

Farmer, W.M. 1970. Swimming gastropods (Opisthobranchia and Prosobranchia). Veliger, 13:73-89.

Gilmer, R.W. 1972. Free-floating mucus webs: a novel feeding adaptation for the open ocean. Science, 176:1239-1240.

______. 1990. In situ observations of feeding behavior of thecosome pteropod molluscs. American Malacological Bulletin, 8:53-59.

Gilmer, R.W. and G.R. Harbison. 1986. Morphology and field behavior of pteropod molluscs: feeding methods in the families Cavoliniidae, Limacinidae and Peraclididae (Gastropoda: Thecosomata). Marine Biology, 91:47-57.

Høisæter, T. 1989. Biological notes on some Pyramidellidae (Gastropoda: Opisthobranchia) from Norway. Sarsia, 74:283-297. 

Kattner, G., W. Hagen, M. Graeve and C. Albers. 1998.  Exceptional lipids and fatty acids in the pteropod Clione limacina (Gastropoda) from both polar oceans.  Marine Chemistry, 61(3-4):219-228.

Lalli, C.M. 1970. Structure and function of the buccal apparatus of Clione limacina (Phipps) with a review of feeding in gymnosomatous pteropods. Journal of Experimental Marine Biology and Ecology, 4:101-118.

Lalli, C.M. and R.W. Gilmer. 1989. Pelagic Snails: The Biology of Holoplanktonic Gastropod Mollusks. Stanford University Press, Stanford, California, 259 pp.

Marcus, E. 1971. Range of Gastropteron pacificum Bergh, 1893 [sic]. Veliger, 13:297.

McGowan, J.A. 1967. Distributional atlas of pelagic molluscs in the California Current region. CALCOFI Atlas No.6 (California Marine Research Committee, 218 pp.

______. 1968. The Thecosomata and Gymnosomata of California. Veliger, 3 (Supplement):103-125.

Mills, C.E. 1994. Seasonal swimming of sexually mature benthic opisthobranch molluscs (Melibe leonina and Gastropteron pacificum) may augment population dispersal. Pp. 313-319 In Reproduction and Development of Marine Invertebrates. S. A. Stricker, W. H. Wilson Jr. and G. L. Shinn (eds.). Johns
Hopkins University Press, Baltimore.

Noji, T.T., et al. 1997Clearance of picoplankton-sized particles and formation of rapidly sinking
aggregates by the pteropod, Limacina retroversa. Journal of Plankton Research, 19(7):863-875.

Norekian, T.P. 1997. Coordination of startle and swimming neural systems in the pteropod mollusk Clione
limacina
: Role of the cerebral cholinergic interneuron. Journal of Neurophysiology, 78(1):308-320.

Panchin, Y.V., P.V. Zelenin and L.B. Popova. 1997. Regeneration of central and peripheral synaptic connections in the locomotor system of the pteropod mollusc Clione limacina. Invertebrate Neuroscience, 3(1):27-40.

Satterlie, R.A., T.P. Norekian and K.J. Robertson. 1997. Startle phase of escape swimming is controlled by pedal motoneurons in the pteropod mollusk Clione limacina. Journal of Neurophysiology, 77(1):272-280.

Seapy, R.R. 1985. The pelagic genus Pterotrachea (Gastropoda: Heteropoda) from Hawaiian waters: A taxonomic review. Malacologia, 26:125-135.

Seapy, R.R. and R.E. Young. 1986. Concealment in epipelagic pterotracheid heteropods (Gastropoda) and cranchiid squids (Cephalopoda). Journal of the Zoological Society of London (A), 210:137-147.

Smith, K.L. Jr. and J.M. Teal. 1973. Temperature and pressure effects on respiration of thecosomatous pteropods. Deep-Sea Research, 20: 853-858.

van der Spoel, S. 1967. Euthecosomata. J. Noorduijn en Zoon N.V., Gorinchem, The Netherlands.

______. 1968. The shell and its shape in Cavioliniidae (Pteropoda, Gastropoda). Beaufortia, 15:185-189.

______. 1972. Notes on the identification and speciation of Heteropoda (Gastropoda). Zoöl. Meded., Leiden, 47:545-560.

______. 1976. Pseudothecosomata, Gymnosomata and Heteropoda (Gastropoda). Bohn, Scheltema and Holkema, Utrecht, The Netherlands, 484 pp.

Suarez-Morales, E. and R. Gasca. 1998. Thecosome Pteropod (Gastropoda) Assemblages of the Mexican Caribbean Sea (1991). Nautilus, 112(2):43-51.

Tarling, G.A.,  J.B.L. Matthews, P. David, O. Guerin and F. Buchholz. 2001. The swarm dynamics of northern krill (Meganyctiphanes norvegica) and pteropods (Cavolinia inflexa) during vertical migration in the Ligurian Sea observed by an acoustic Doppler current profiler.  Deep Sea Research Part I : Oceanographic Research, 48(7):1671-1686. 

Tesch, J.J. 1949. Heteropoda. “Dana” Report ,34:1-53.

______ 1950. The gymnosomata II. “Dana” Report , 36:1-15.

Thiriot-Quievreux, C. 1973. Heteropoda. Oceanography and Marine Biology Annual Review, 11:237-261.

______ and R.R. Seapy. 1997. Chromosome studies of three families of pelagic heteropod molluscs (Atlantidae, Carinariidae, and Pterotracheidae) from Hawaiian waters. Canadian Journal of Zoology, 75(2):237-244.

Thompson, T.E. and I. Bennett. 1969. Physalia nematocysts: utilized by mollusks for defense. Science, 166:1532-1533.

Wang, L., Z. Jian and J. Chen. 1997.  Late Quaternary pteropods in the South China Sea: carbonate
preservation and paleoenvironmental variation.  Marine Micropaleontology, 32(1-2):115-126.

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Cnidarian References

Listed here are a variety of scientific papers that relate to the study of cnidarian jellies. These papers are published in scientific journals that are not available in public libraries – you will need access to a university library or online sources. Note that references with author names in color are links to abstracts (summaries) provided by several publishing companies that produce scientific journals. In most cases, the full journal papers are available online by paid subscription (check the home page of each publishing company for details).

To search for online literature, use the new Google tool below (About Google Scholar). Use any information available – author, topic, title, words that appear in title, etc. If you see a reference below that strikes your fancy, use that information for the search. Make your query as specific as possible to limit the number of search results. If you’re lucky, you’ll come up with a link to the complete research paper, or at least an abstract. This is a new service so don’t expect everything to be online, but with time it should improve.

Google Scholar


Abe, Y. and M. Hisada. 1969. On a new rearing method of common jellyfish, Aurelia aurita. Bulletin Marine Biol. Stn. Asamushi, 13: 205–209.

Acker, T.S. 1976. Craspedacusta sowerbyi: an analysis of an introduced species. Pages 219-226 in G.O.
Mackie, editor. Coelenterate ecology and behavior. Plenum Press, New York. 

Acuña, J. L., D. Deibel, and S. Sooley. 1994. A simple device to transfer large and delicate planktonic organisms. Limnology and Oceanography, 39: 2001–2003.

Afzelius, B.A. and A. Franzen. 1971. The spermatozoon of the jellyfish Nausithoe. Journal of Ultrastructure
Research, 37: 186-199.

Agassiz, A., 1883. Exploration of the surface fauna of the Gulf Stream. III. Part 1. The Porpitidae and Velellidae. Memoirs of the Museum of Comparative Zoology at Harvard College 8: 16 pp. + 12 plates.

Alvariño, A. 1971. Siphonophores of the Pacific, with a review of the world distribution. Bulletin of the Scripps Institution of Oceanography, 16:1-432.

Anderson, P.A.V.  1977.  Electrically coupled, photosensitive neurons control swimming in a jellyfish.  Science, 197: 186-188.

Arai, M. N. 1988. Interactions of fish and pelagic coelenterates. Canadian Journal of Zoology,  66: 1913-1927.

_____. 1991. Attraction of Aurelia and Aequorea to prey. Hydrobiologia, 216–217: 363–366.

_____. 1997. A Functional Biology of Scyphozoa. Chapman and Hall, London, 316 pp.

_____.
2001. Pelagic cnidarians and eutrophication: a review.  Hydrobiologia 451 (Developments in Hydrobiology, 155):1-9. 

Arai, M.N. and A. Brinckman-Voss. 1980. Hydromedusae of British Columbia and Puget Sound. Canadian Bulletin of Fisheries and Aquatic Sciences. 204, 192 pp.

_____. 1983. A new species of Amphinema: Amphinema platyhedos n. sp. (Cnidaria, Hydrozoa, Pandeidae) from the Canadian West Coast. Canadian Journal of Zoology, 61:2179-2182.

Arai, M.N., M.J. Cavey, and B.A. Moore. 2000. Morphology and distribution of a deep-water Narcomedusa (Solmarisidae) from the north-east Pacific. Scientia Marina, supplement 1:55-62. 

Arkett, S.A. and A.N. Spencer. 1986. Neuronal mechanisms of a hydromedusan shadow reflex.  I. Identified reflex components and sequence of events. Journal of Comparative Physiology,  159: 201-213.

Arkhipkin, A. and V. Bizikov. 1996. Possible imitation of jellyfish by the squid paralarvae of the family Gonatidae (Cephalopoda, Oegopsida). Polar Biology, 16(7):531-534.

Aerne, B.L. 1996. The hydrozoan life cycle: a small secreted protein is involved in specification of the polyp stage. Development, Genes and Evolution, 206(5):337-343.

Avian, M. 1986. Temperature influence on in vitro reproduction and development of Pelagia noctiluca (Forskal). Bollettino di Zoologia, 53: 385-391.

_____., L. Rottini Sandrini and F. Stravisi. 1991. The effect of seawater temperature on the swimming activity of Pelagia noctiluca (Forsskal). Bollettino di Zoologia, 58(2): 135-142.

Båmstedt, U.,  M.B. Martinussen  and S. Matsakis. 1994. Trophodynamics of the two scyphozoan jellyfishes, Aurelia aurita and Cyanea capillata, in western Norway. ICES Journal of Marine Science, 51(4):369-382.

Båmstedt, U., H. Ishii and M. B. Martinussen. 1997. Is the scyphomedusa Cyanea capillata (L.) dependent on gelatinous prey for its early development? Sarsia, 82:269-273.

Båmstedt, U., J. H. Fosså, M. B. Martinussen and A. Fosshagen. 1998. Mass occurrence
of the physonect siphonophore Apolemia uvaria (LESUEUR) in Norwegian waters. Sarsia:83:79-85. 

Bamstedt, U.,  J. Lane and M.B. Martinussen 1999.  Bioenergetics of ephyra larvae of the scyphozoan jellyfish Aurelia aurita in relation to temperature and salinity.  Marine Biology, 135(1):89-98.

Båmstedt, U., B. Wild, and M. Martinussen. 2001. Significance of food type for growth of ephyrae Aurelia aurita (Scyphozoa). Marine Biology, 139(4):641-650.

Båmstedt, U., S. Kaartvedt, and M. Youngbluth. 2003. An evaluation of acoustic and video methods to estimate the abundance and vertical distribution of jellyfish. Journal of Plankton Research, 25(11): 1307-1318.

Bieri, R.1959. Dimorphism and size distribution in Velella and Physalia. Nature, London, 184: 1333-1334.

_____. 1977. A morphometric study of Velella (Hydrozoa) from different oceans.  Publications Seto Marine Biological Lab., 24: 59-62.

Bigelow, H.B. 1911. Reports on the scientific results of the expedition to the eastern tropical Pacific by the U.S. Fish Commission steamer “Albatross” 1904-1905. XXII. The siphonophorae. Memoirs of the Museum of Comparative Zoology, Harvard College, 38:171-401, 32 pls.

______ 1912. Reports on the scientific results of the expedition to the eastern tropical Pacific by the U.S. Fish Commission steamer “Albatross” 1904-1905. XXVI. The ctenophores. Bulletin of the Museum of Comparative Zoology, Harvard College, 54:369-404, 2 pls.

Bischoff, A., J. Fleck, and D.K. Hofmann. 1991. Phorbol esters induce metamorphosis in
Cassiopea andromeda
and Cassiopea xamachana (Cnidaria:Scyphozoa). Proceedings of the German Zoological Society, 84:484.


Blanquet, R.S. 1972. Temperature acclimation in the medusa, Chrysaora quinquecirrha. Comp. Biochem. Physiol., 43B:717-723.

 

Bloom, D.A., J.W.  Burnett and P. Alderslade. 1998.  Partial purification of box jellyfish (Chironex
fleckeri
) nematocyst venom isolated at the beachside. Toxicon, 36(8):1075-1085.

Boero, F. and J. Bouillon. 1989. The life cycles of Octotiara russelli and Stomotoca atra (Cnidaria,
Anthomedusae, Pandeidae). Zoologica Scripta, 18(1):1-7.

Boothroyd, I.K.G., M.K. Etheredge, and J.D. Green. 2002. Spatial distribution, size structure, and prey of Craspedacusta sowerbyi Lankester in a shallow New Zealand lake . Hydrobiologia, 468(1-3):23-32.

Bouillon, J. 1999. Hydromedusae. Pages 385-465 in D. Boltovsky, editor. South Atlantic zooplankton. Backhuys Publishers, Leiden, The Netherlands. 

Bouillon, J., F. Boero, F. Cicogna, J.M. Gili and R.G. Hughes. 1992. Non-siphonophoran Hydrozoa: what are we talking about? Scientia Marina, 56:279-284.

Bouillon, J. and T.J. Barnett. 1999. The marine fauna of New Zealand: Hydromedusae (Cnidaria: Hydrozoa). NIWA Biodiversity Memoir, 113:1-136.

Brewer, R. H. 1976. Larval settling behavior in Cyanea capillata (Cnidaria: Scyphozoa). Biological Bulletin, 150: 183–199.

_____. 1978. Larval settlement behavior in the jellyfish Aurelia aurita (Linnaeus) (Scyphozoa: Semaeostomeae). Estuaries, 1: 120–122.

_____. 1984. The influence of the orientation, roughness, and wettability of solid surfaces on the behavior and attachment of planulae of Cyanea (Cnidaria: Scyphozoa). Biological Bulletin, 166: 11–21.

_____. 1989. The annual pattern of feeding, growth, and sexual reproduction in Cyanea in the Niantic River estuary, Connecticut.  Biological Bulletin, 176: 272-281.

_____ and J. S. Feingold. 1991. The effect of temperature on the benthic stages of Cyanea (Cnidaria: Scyphozoa), and their seasonal distribution in the Niantic River estuary, Connecticut. Journal Experimental Marine Biology and Ecology, 152: 49–60.

Bieri, R., 1959. Dimorphism and size distribution in Velella and Physalia. Nature, London 184: 1333-1334.

_____. 1970. The food of Porpita and niche separation in three neuston coelenterates. Publications of the Seto Marine Biological Laboratory, 17: 305-307.

_____. 1977a. A morphometric study of Velella (Hydrozoa) from different oceans. Publications of the Seto Marine Biological Laboratory, 24: 59-62.

_____. 1977b. The ecological significance of seasonal occurrence and growth rate of Velella (Hydrozoa). Publications of the Seto Marine Biological Laboratory, 24: 63-76.

Bigelow, H. B., 1911c. The Siphonophorae. Reports of the scientific research expedition to the tropical Pacific. Albatross XXIII. Mem. Mus. Comp. Zool. Harv. 38: 173-401, 132 pls.

Brinckmann, A., 1964b. Observations on the structure and development of the medusa of Velella velella (Linne 1758). Videnskabelige Meddelelser fra Dansk naturhistorisk Forening bd. 126: 327-336.

Brierley, A.S., et.al. 2001. Acoustic observations of jellyfish in the Namibian Benguela. Marine Ecology Progress Series, 210:55-66.

Brinkmann-Voss, A. 1970. Anthomedusae/Athecata (Hydrozoa, Cnidaria) of the Mediterranean. Part I. Capitata. Fauna Flora Golf. Neapel, 39: 1–96.

 _____ 1985. Hydroids and medusae of Sarsia apicula (Murbach and Shearer, 1902) and Sarsia princeps (Haeckel, 1879) from British Columbia and Puget Sound with an evaluation of their systematic characters. Canadian Journal of Zoology, 63:673-681.

Brodeur, R. D. 1998. In situ observations of the association between juvenile fishes and scyphomedusae in
the Bering Sea.  Marine Ecology Progress Series, 163: 11-20.

Brodeur, R.D., C. E. Mills, J. E. Overland, G.E. Walters and J. D. Schumacher. 1999. Evidence for a substantial increase in gelatinous zooplankton in the Bering Sea, with possible links to climate change. Fisheries Oceanography, 8(4):296-306. 

Buecher, E, C. Sparks, A. Brierley, H. Boyer and M. Gibbons. 2003. Biometry and size distribution of Chrysaora hysoscella (Cnidaria, Scyphozoa) and Aequorea aequorea (Cnidaria, Hydrozoa) off Namibia with some notes on their parasite Hyperia medusarum.  Journal of Plankton Research, 23(10):1073-1080.

Bullock, T. H. 1943. Neuromuscular facilitation in scyphomedusae. Journal Cell. Comparitive Physiology, 22: 251–272.

Burd, B.J. and R. E. Thomson. 2000.  Distribution and relative importance of jellyfish in a region of hydrothermal venting.  Deep Sea Research Part I : Oceanographic Research (47)9:1703-1721.

Burke, W.D. 1975. Pelagic Cnidaria of Mississippi Sound and adjacent waters. Gulf Research Reports, 5:23-38.  

Burnett, J.W. 2001. Medical aspects of jellyfish envenomation: parthenogenesis, case reporting and therapy. Hydrobiologia 451 (Developments in Hydrobiology, 155):1-9. 

Burnett, J.W., et al. 1998. Autonomic neurotoxicity of jellyfish and marine animal venoms.  Clinical
Autonomic Research, 8(2):125-130.

Calder, D.R. 1971. Hydroids and hydromedusae of the southern Chesapeake Bay. Virginia Institute of Marine Science, Special Paper in Marine Science 1, Gloucester Point.

_____. 1971. Nematocysts of polyps of Aurelia, Chrysaora and Cyanea and their utility in identification.  Transactions of the American Microscope Society,  90: 269-274.

____. 1974a. Nematocysts of the coronate scyphomedusa, Linuche unguiculata, with a brief reexamination of scyphozoan nematocyst classification. Chesapeake Science, 15: 170-173.

_____. 1974b. Strobilation of the sea nettle, Chrysaora quinquecirrha, under field conditions. Biological Bulletin, 146: 326–334.

Cargo, D. G. 1975. Comments on the laboratory culture of scyphozoa. Pp. 145–154 in Culture of Marine Invertebrate Animals; Proceedings, W. L. Smith and M. H. Chanley, eds. Plenum Press, New York.

_____ and L.P. Schultz. 1967. Further observations on the biology of the sea nettle and jellyfishes in Chesapeake Bay. Chesapeake Science, 8:209-220.

_____ and G.E. Rabenold. 1980. Observations on the asexual reproduction activities of the sessile stages of the sea nettle Chrysaora quinquecirrha. Estuaries, 3:20-27.

Caughlan, D. 1984. The captive husbandry of Aurelia aurita. Drum and Croaker, 21(1): 46-49.

Chapman, D.M. 1999. Microanatomy of the bell rim of Aurelia aurita (Cnidaria: Scyphozoa). Canadian Journal of Zoology, 77:34-46.

_____. 2001. Development of the tentacles and food groove in the jellyfish Aurelia aurita (Cnidaria: Scyphozoa). Canadian Journal of Zoology, 79:623-632.

Chen Jiekang and D. Gengwu. 1983. Effect of temperature on the strobilation of jellyfish (Rhopilema esculenta Kishinouye – Scyphozoa, Rhizostomeae). Acta Zoologica Sinica, 29(3):195-206 [In
Chinese, with English abstract]. 

Condon, R.H., M.B. Decker and J.E. Purcell. 2001. Effects of low oxygen on survival and asexual reproduction of scyphozoan polyps (Chrysaora quinquecirrha).  Hydrobiologia 451 (Developments
in Hydrobiology, 155):89-95.

Cones, H.N. Jr. 1969. Strobilation of Chrysaora quinquecirrha polyps in the laboratory. Virginia Journal of Science, 20:16-18.

Conklin, E.G. 1908. The habits and early development of Linerges mercurius. Carnegie Institution of Washington, 103:155-170.

_____. 1909. Two peculiar actinian larvae from Tortugas  Florida. Carnegie Institution of Washington, 103:171-186.

Cornelius, P.F.S. 1982. Hydroids and medusae of the family Campanulariidae recorded from the eastern North Atlantic, with a world synopsis of genera. Bulletin of the British Museum (Natural History). Zoology, 42:37-148.  

Costello, J.H. and S.P. Colin. 1994. Morphology, fluid motion and predation by the scyphomedusae Aurelia aurita. Marine Biology, 121:327-334.  

_____. 1995. Flow and feeding by swimming scyphomedusae. Marine Biology, 124:399-406.

Currie, B. and Y. K. Wood. 1995. Identification of Chironex fleckeri envenomation by nematocyst recovery from skin.  Medical Journal of Australia, 162: 478-480.

Custance, D. R. N. 1964. Light as an inhibitor of strobilation in Aurelia aurita. Nature, 204:1219–1220.

_____. 1966. The effect of a sudden rise in temperature on strobilae of Aurelia aurita. Experientia, 22:588- 589.

D’Ambra, I., J.H. Costello and F. Bentivegna. 2001. Flow and prey capture by the scyphomedusa Phyllorhiza punctatq von Lendenfeld, 1884. Hydrobiologia 451 (Developments in Hydrobiology, 155):1-9. 

Dawson, M. N. 2000. Variegated mesocosms as alternatives to shore-based planktonkreisels: notes on the husbandry of jellyfish from marine lakes. Journal of Plankton Research, 22:1673–1682.

_____. 2003. Macro-morphological variation among cryptic species of the moon jellyfish, Aurelia (Cnidaria: Scyphozoa). Marine Biology, 143(2):369-379.

_____. 2004. Some implications of molecular phylogenetics for understanding biodiversity in jellyfishes, with emphasis on Scyphozoa. Hydrobiologia, 530(1):249-260. 

Dawson, M.N. and L.E. Martin. 2001. Geographic variation and ecological adaptation in Aurelia (Scyphozoa,
Semaeostomeae): some implications from molecular phylogenetics. Hydrobiologia 451 (Developments in Hydrobiology, 155):259-273. 

Dawson, M.N., L.E. Martin and L.K. Penland. 2001. Jellyfish swarms, tourists, and the Christ-child. Hydrobiologia 451 (Developments in Hydrobiology, 155):1-9.

Delap, M. J. 1907. Notes on the rearing, in an aquarium, of Aurelia aurita, L. and Pelagia perla (Slabber). Report on the Sea and Inland Fisheries of Ireland for 1905, Part II. Scientific Investigations: 160-164 + 2 plates.

Dillon, T.M. 1977. Effects of acute change in temperature and salinity on pulsation rates in ephyrae of the scyphozoan Aurelia aurita. Marine Biology, 42:31-35.

Eaken, R.M. and J.A. Westfall. 1962.  Fine structure of photoreceptors in the hydromedusan, Polyorchis penicillatus. PNAS, 48: 826-833.

Eckelbarger, K.J. and R.J. Larson. 1993. Ultrastructural study of the ovary of the sessile scyphozoan, Haliclystus octoradiatus (Cnidaria: Stauromedusae).  Journal of Morphology, 218:225-236.

Edwards, C., 1966. Velella velella (L.): The distribution of its dimorphic forms in the Atlantic Ocean and the Mediterranean, with comments on its nature and affinities. In Barnes, H. (ed.), Some contemporary studies in marine science. George Allen and Unwin Ltd., London: 283-296.

_____. 1968. Water movements and the distribution of hydromedusae in British and
adjacent waters. Sarsia, 34:331-346.

Elliott, J.K. and W. C. Leggett. 1997. Influence of temperature on size-dependent predation by a fish (Gasterosteus aculeatus) and a jellyfish (Aurelia aurita) on larval capelin (Mallotus villosus). Canadian
Journal of Fisheries and Aquatic Sciences, 54:2759-2766.

Fautin, D. 2002. Reproduction in Cnidaria. Canadian Journal of  Zoology, 80: 1735-1754.

Fields, W. G. and G. O. Mackie, 1971. Evolution of the Chondrophora: evidence from behavioural studies on
Velella. Journal of the Fisheries Research Board Canada, 28: 1595-1602.

Fitt, W.K. and D.K. Hofmann. 1985. Chemical induction of settlement and metamorphosis of planulae and buds of the reef-dwelling coelenterate Cassiopea andromeda. Proc. Fifth International Coral Reef Symposium, 5:239-244.

Fitt, W.K., D.K. Hofmann, M. Wolk, and M. Rahat. 1987.  Requirement of exogenous inducers for the development of axenic larvae and buds of Cassiopea andromedaMarine Biology, 94:415-422.

Fitt, W.K. and  K. Costley.  1998. The role of temperature in survival of the polyp stage of the tropical
rhizostome jellyfish Cassiopea xamachana.  Journal of Experimental Marine Biology and Ecology, 222(1-2):79-91.

Fleck, J. and D.K. Hofmann. 1990.  The efficiency of metamorphosis inducing oligopeptides in Cassiopea
species (Cnidaria:Scyphozoa) depends on both primary structure and amino and carboxiterminal substituents. Proceedings German Zoological Society, 83:452-453.

_____. 1995.  In vivo binding of a biologically active peptide in vegetative buds of the scyphozoan Cassiopea  andromeda: demonstration of receptor-mediated induction of metamorphosis. 
Marine Biology, 122:447-451.

Fleck, J. and W.K. Fitt. 1999.  Degrading mangrove leaves of Rhizophora mangle Linne provide a natural cue for settlement and metamorphosis of the upside down jellyfish Cassiopea xamachana Bigelow.  Journal of Experimental Marine Biology and Ecology, 234(1):83-94.

Fleck, J., W.K. Fitt and M.G. Hahn.  1999.  A proline-rich peptide originating from decomposing mangrove leaves is one natural metamorphic cue of the tropical jellyfish Cassiopeia xamachana. Marine Ecology Progress Series, 183(115-124).

Foerster, R.E. 1923. The Hydromedusae of the west coast of North America, with special reference to those of the Vancouver Island Region. Contributions to Canadian Biology (New Series), 1:219-277, 5 pls.

Fosså, J.H. 1992. Mass occurrence of Periphylla periphylla (Scyphozoa, Coronatae) in a Norwegian fjord. Sarsia, 77:237-251.

Francis, L., 1985. Design of a small cantilevered sheet: the sail of Velella velella. Pacific Science, 3: 1-15.

_____. 1991. Sailing downwind: aerodynamic performance of the Velella sail.  Journal of Experimental Biology, 158:117-132.

Frandsen, K.T. and H.U. Riisgaard. 1997.  Size dependent respiration and growth of jellyfish, Aurelia
aurita. 
Sarsia, 82(4):307-312.

Freeman, G. and E.B. Ridgway. 1990. Cellular and intracellular pathways mediating the metamorphic stimulus in hydrozoan planulae. Roux’s Archives Developmental Biology 199: 63–79.

Fukuda, Y. and T. Naganuma. 2001. Potential dietary effects on the fatty acid composition of the common jellyfish Aurelia aurita. Marine Biology, 138(5):1029-1035.

Gasca, R. 1999. Siphonophores (Cnidaria) and summer mesoscale features in the Gulf of Mexico. Bulletin of Marine Science, 65:75-89.

Gatz, A.J., V.S. Kennedy and J.A. Mihursky. 1973. Effects of temperature on activity and mortality of the scyphozoan medusa, Chrysaora quinquecirrha. Chesapeake Science, 14(3):171-180.

Gershwin, L. 2001. Systematics and biogeography of the jellyfish Aurelia labiata (Cnidaria: Scyphozoa). Biological Bulletin, 201(1):104- .

_____. 2003. Scyphozoa and cubozoa of Guam. Micronesia, 35-36:156-158.

_____ and M.S. Schaadt. 1995. Strobilation induction in cold-water Aurelia aurita at the Cabrillo Marine Aquarium. Drum and Croaker, 26:4-8.

Gilchrist, F. C. 1937. Rearing of the scyphistoma of Aurelia in the laboratory. Culture methods of
invertebrate animals. P.S.G. e. alia. Ithaca: 143.

_____. 1937. Budding and locomotion in the scyphistomas of Aurelia. Biological Bulletin (Woods Hole), 72: 99-124, figs. 1-9.

Gili, J.M., J. Bouillon, F. Pages, A. Palanques, P. Puig, and S. Heussner. 1998. Origin and biogeography of the deep-water Mediterranean Hydromedusae including the description of two new species collected in submarine canyons of northwestern Mediterranean. Scientia Marina, 62:113-134.

Gili, J.M., et al. 2000.  A multidisciplinary approach to the understanding of hydromedusan populations inhabiting Mediterranean submarine canyons. Deep Sea Research Part I : Oceanographic Research, 47(8):1513-1533. 

Graham, W.M. 2001. Numerical increases and distributional shifts of Chrysaora quinquecirrha (Desor) and Aurelia aurita (Linne) (Cnidaria: Scyphozoa) in the northern Gulf of Mexico. Hydrobiologia 451 (Developments in Hydrobiology, 155):1-9.

Graham, W.M., D.L. Martin, D.L. Felder, V.L. Asper, and H.M. Perry. 2003. Ecological and economic implications of a tropical jellyfish invader in the Gulf of Mexico. Biological Invasions, 5(1-2):53-69.

Greenberg, N., R.L. Garthwaite, and D.C. Potts. 1996. Allozyme and morphological evidence for a newly introduced species of Aurelia in San Francisco Bay, California. Marine Biology, 125:401-410.

Grigoriev, et. al. 1996. A cardiac-like sodium current in motor neurons of a jellyfish. Journal of
Neurophysiology,  76:2240-2249.

Groat, C. S., C. R. Thomas, and K. Schurr. 1980. Improved culture of Aurelia aurita scyphistomae for bioassay and research. Ohio Journal of Science, 80:83–87.

Gutschick, R. C. and J. Rodriguez, 1990. By-the-wind sailors from a late Devonian foreshore environment in western Montana. Journal of Paleontology, 64: 31-39.

Gwilliam, G.F. 1956. Studies on West Coast Stauromedusae. Ph.D. Dissertation, University of California, Berkeley. 

Haddock, S. H. D., T. J. Rivers, and B. H. Robison. 2001. Can coelenterates make coelenterazine? Dietary requirements for luciferin in cnidarian bioluminescence. Proceedings of the National Academy of
Sciences USA, 98:11148–11151.

Hagadorn, J. W., R.H. Dott, and D. Damrow. 2002. Stranded on a late Cambrian shoreline: Medusae from central Wisconsin. Geology, 30(2):147-150.

Hamada, T. 1977. Medusae and their conditions to be fossilized. Fossils, 27:61-75.

Hamner, W. M. and D. Schneider. 1986. Regularly spaced rows of medusae in the Bering Sea: Role of Langmuir circulation. Limnology and Oceanography, 31:171–177.

Hand, C. 1954. Three Pacific species of “Lar” (including a new species), their hosts, medusae, and relationships (Coelenterata, Hydrozoa). Pacific Science, 8:51-67.

Hanelt, B., D. van Schyndel, C.M. Adema, L.A. Lewis, and E.S. Loker. 1996. The phylogenetic position of Rhopalura ophiocomae (Orthonectida) based on 18S ribosomal DNA sequence analysis. Marine Biology Evolution, 13:1187-1191. 

Hanson, L.J. 1997.  Capture and digestion of the scyphozoan jellyfish Aurelia aurita by Cyanea
capillata
and prey response to predator contact. Journal of Plankton Research, 19(2):195-208.

Hansson, L.J. 1997.  Effect of temperature on growth rate of Aurelia aurita (Cnidaria, Scyphozoa) from Gullmarsfjorden, Sweden.  Marine Ecology Progress Series, 161:145-153.

Harbison, G. R., K. L. Smith, Jr., and R. H. Backus. 1973. Stygiomedusa fabulosa from the North Atlantic: its taxonomy, with a note on its natural history. Journal of the Marine Biological Association U.K., 53:615-617.

Hayashi, Y. 1998.  Detrimental effect of moon jellyfish Aurelia aurita on cooling of sea water in the fish hold of set net fishing boat. Nippon Suisan Gakkaishi, 64: 1046-1052.

Hirano, Y.M. 1986. Species of Stauromedusae from Hokkaido, with notes on their metamorphosis. Journal of the Faculty of Science, Hokkaido University, Series 6 (Zoology), 24:182-201. 

_____. 1997. A review of a supposedly circumboreal species of Stauromedusa, Haliclystus auricula (Rathke, 1806). Proceedings of the 6th International Conference on Coelenterate Biology, 1995:247-252.

Hiromi, J., T. Yamamoto, Y. Koyama and S. Kadota. 1995. Experimental study of predation of scyphopolyp Aurelia aurita. Bulletin of the College of Agriculture and Veterinary Medicine Nihon University, 0(52):126-130. 

Hirst, A.G. and C.H. Lucas. 1998. Salinity influences body weight quantification in the scyphomedusa Aurelia aurita: important implications for body weight determination in gelatinous zooplankton.
Marine Ecology Progress Series, 165:259-269. 

Hofmann, D.K., R. Neumann, and K. Henne. 1978.  Strobilation, budding, and initiation of scyphistoma morphogenesis in the rhizostome Cassiopea andromeda (Cnidaria: Scyphozoa).  Marine Biology, 47:161-176.

Hofmann, D.K. and B. P. Kremer. 1981. Carbon metabolism and strobilation in Cassiopea andromeda (Cnidaria: Scyphozoa): Significance of endosymbiontic dinoflagellates. Marine Biology, 65: 25-33.

Hofmann, D.K., K. Bernardy, and U. Brand. 1984. Asexual reproduction in Cassiopea andromeda (Scyphozoa): Induction of settlement and metamorphosis in vegetative buds. In: W. Engels (Ed.) Advances in Invertebrate Reproduction, 3:592, Elsevier: Amsterdam.

Hofmann, D.K. and U. Brand. 1986. Is induction of polyp morphogenesis in Cassiopea andromeda
(Cnidaria) based on interorganismic chemical signals? 
Advances in Invertebrate Reproduction, 4:519.

Hofmann, D.K. and U. Brand. 1987.  Induction of metamorphosis in the symbiotic scyphozoan Cassiopea andromeda: Role of marine bacteria and of biochemicals. Symbiosis, 4:99-116.

Hofmann, D.K. and T.G. Honegger. 1990.  Bud formation and bud metamorphosis in Cassiopea
andromeda
(Cnidaria, Scyphozoa): A developmental and ultrastructural study. Marine Biology, 105:509-518.

Hofmann, D.K. and M.Gottlieb. 1991. Bud formation in Cassiopea andromeda: Epithelial dynamicsand fate map. Hydrobiologia, 216/217:53-59.

Hofmann, D.K. and G. Henning. 1991.  Effects of axenic culture on asexual reproduction and metamorphosis in the symbiotic scyphozoan Cassiopea andromeda.  Symbiosis, 10:83-93.

Hofmann, D.K., B. Manitz, and B. Reckenfelderbäumer. 1992. Metamorphosis in the scyphozoan Cassiopea
andromeda.
Cellular and morphogenetic responses to exogenous inducers.
 Proceedings 7th International Coral Reef Symposium, 463-470.

Hofmann, D., W.K. Fitt, and J. Fleck. 1996. Checkpoints in the lifecycle on Cassiopea spp.: control of metagenesis and metamorphosis in a tropical jellyfish.  International Journal of Developmental Biology, 40:331-338.

Hofmann, D.K. andG. Crow. 2002. Induction of larval metamorphosis in the tropical scyphozoan Mastigias papua: striking similarity with upside down-jellyfish Cassiopea spp. (with notes on  related species). Vie Milieu, 52(4):141-147.

Hofmann, D.K. and M.G. Hadfield. 2002. Hermaphroditism, gonochorism, and asexual reproduction in Cassiopea sp.: an immigrant in the Islands of Hawai’i.  Invertebrate Reproduction & Development, 41(1-3): 215-221.

Hogler, J. A. and R. A. Hanger. 1989. A New Chondrophorine Hydrozoa Velellidae from the Upper Triassic of Nevada Usa. Journal of Paleontology, 63: 249-251.

Horridge, G.A. (1959).  The nerves and muscles of medusae. VI. The Rhythm. Journal of   Experimental Biology,  36:72-91.

Hsieh, P.Y-H, F-M Leong and J. Rudloe. 2001. Jellyfish as food.  Hydrobiologia 451 (Developments in Hydrobiology, 155):1-9. 

Huxley, T. H. 1859. The Oceanic Hydrozoa: A description of the Calycophoridae and Physophoridae observed during the voyage of the H.M.S. “Rattlesnake” in the years 1846-1850. Ray Society, London, x + 143, with 112 plates pp.

Hyman, L.H. 1940. Observations and experiments on the physiology of medusae. Biological Bulletin, 79:282-296. 

Isaeva, V.V., A.V. Chernyshev, and D.Y. Shkuratov. 2001. Quasi-fractal organization of the gastrovascular system of the jellyfish Aurelia aurita: Order and chaos. Doklady Biochemistry and Biophysics, 377 (1-6): 110-112.

Ishii, H. and U. Baamstedt.  1998. Food regulation of growth and maturation in a natural population of Aurelia aurita (L.).  Journal of Plankton Research, 20(5):805-816.

Ishii, H. and F. Tanaka. 2001. Food and feeding of Aurelia aurita in Tokyo Bay with an analysis of stomach contents and a measurement of digestion times. Hydrobiologia 451 (Developments in Hydrobiology, 155):311-320. 

Jankowski, T. 2001. The freshwater medusae of the world – a taxonomic and systematic literature study with some remarks on other inland water jellyfish. Hydrobiologia, 462(1-3): 91-113. 

_____. 2004. Predation of freshwater jellyfish on Bosmina : the consequences for population dynamics, body size, and morphology. Hydrobiologia, 530(1):521-528.

Jarms, G,  U. Baemstedt, H. Tiemann,  M.B. Martinussen and J.H. Fossae. 1999.  The holopelagic life cycle of the deep-sea medusa Periphylla periphylla (Scyphozoa, Coronatae).  Sarsia, 84(1):55-65.

Jarms, G., H. Tiemann, and U. Båmstedt. 2002. Development and biology of Periphylla periphylla (Scyphozoa: Coronatae) in a Norwegian fjord. Marine Biology, 141(4):647-657.

Jarms, G., A.C. Morandini, et al. 2002. Cultivation of polyps and medusae of Coronatae (Cnidaria, Scyphozoa) with a brief review of important characters.  Helgolander Marine Res., 56:203-210.

Jiang Shuang and L.N.C. Jiekang. 1993. Effect of temperature, salinity and light on the germination of the podocyst of Rhopilema esculenta Kishinouye. Fisheries Science (Liaoning), 12(9):1-4 [In Chinese, with English and Chinese summaries].

Johnson, D.R., H.M. Perry and W.D. Burke. 2001. Developing jellyfish strategy hypotheses using circulation models.  Hydrobiologia 451 (Developments in Hydrobiology, 155):213-221. 

Kass-Simon, G. and A.A. Scappaticci. 2002. The behavioral and developmental physiology of nematocysts. Canadian Journal of Zoology, 80:1772–1794.

Keen, S. L. 1987. Recruitment of Aurelia aurita (Cnidaria: Scyphozoa) larvae is position-dependent, and independent of conspecific density, within a settling surface. Marine Ecology Progress Series, 38:151–160.

Kendall, J.M. and M.N. Badminton. 1998. Aequorea victoria bioluminescence moves into an exciting new era. Trends in Biotechnology, 16(5):216-224.

Kingsford, M.J., K.A. Pitt and B.M. Gillanders. 2000. Considerations for the management of fisheries for jellyfish with special reference to Catostylus mosaicus (O. Rhizostomeae) in Australia. Oceanography and Marine Biology: An Annual Review, 38:85-156.

Kinoshita, J., J. Hiromi and S. Kadota. 1997.  Do respiratory metabolic rates of the scyphomedusa Aurelia aurita scale isometrically throughout ontogeny in a sexual generation? Hydrobiologia, 347(1-3):51-55.

Kirkpatrick, P.A. and P.R. Pugh. 1984. Siphonophores and Velellids. E.J. Brill / Dr. W. Backhuys, London, 154 pp.

Komai, T. 1935. On Stephanoscyphus and Nausithoë. Mem. Coll. Sci. Kyoto, 10: 289-339.

Kramp, P.L. 1961. Synopsis of the medusae of the world. Journal of the Marine Biological Association, U.K., 40:1-469.

_____. 1965. The Hydromedusae of the Pacific and Indian Oceans. Dana Report, 63:1-162.

______. 1968. The Hydromedusae of the Pacific and Indian Oceans: Sections II and III. Dana Report, 72:1-200.

Kremer, P., et al. 1990. Significance of photosynthetic endosymbionts to the carbon budget of the
scyphomedusa Linuche unguiculata. Limnology and Oceanography 35: 609-624.

Kroiher, M. and S. Berking. 1999. On natural metamorphosis inducers of the cnidarians Hydractinia echinata (Hydrozoa) and Aurelia aurita (Scyphozoa). Helgoland Marine Research, 53(2):118-121.

Lambert, R. J. 1935. Jellyfish. The difficulties of the study of their life cycle and other problems. Essex Naturalist, 25:70-86, pl. III-IV.

_____. 1935b. Observations on the scyphomedusae of the Thames estuary and their metamorphosis. Travaux de la Station Zoologique de Wimereux, 12: 281-307.

Lange, J. and R. Kaiser. 1995. The maintenance of pelagic jellyfish in the Zoo-Aquarium Berlin. International Zoo Yearbook, 34:59-64.

Larson, R.J. 1976. Cubomedusae: feeding – functional morphology, behavior and phylogenetic position. Pp. 237-245 In Coelenterate Ecology and Behavior, G.O. Mackie (ed.). Plenum Press, New York.

_____. 1976. Marine flora and fauna of the northeastern United States. Cnidaria: Scyphozoa.  NOAA Technical Report National Marine Fisheries Service Circular 397.  

______. 1979. Feeding in coronate medusae (Class Scyphozoa, Order Coronatae). Marine Behavior and Physiology, 6:123-129.

______. 1980. The medusa of Velella velella (Linnaeus, 1758) (Hydrozoa, Chondrophorae). Journal of Plankton Research, 2:183-186.

_____. 1986. Pelagic Scyphomedusae (Scyphozoa: Coronatae and Semaeostomeae) of the Southern Ocean. Antarctic Research Series, 41(3):59-165. 

_____. 1988. Kyopoda lamberti gen. nov., sp. nov., an atypical Stauromedusa (Scyphozoa, Cnidaria) from the eastern Pacific, representing a new family. Canadian Journal of Zoology, 66:2301-2303. 

______. 1990. Scyphomedusae and Cubomedusae from the eastern Pacific. Bulletin of Marine Science, 47:546-556.

_____. 1991. Why jellyfish stick together—Caribbean thimble jellies travel in the same circles. Natural
History, 66–71.

______. 1992. Riding Langmuir circulations and swimming in circles: a novel clustering behavior by the scyphomedusa Linuche unguiculata. Marine Biology, 112:229-235.

Larson, R.J., and A.C. Arneson, 1990. Two medusae new to the coast of California: Carybdea marsupialis (Linnaeus, 1758), a Cubomedusa and Phyllorhiza punctata von Lendenfeld, 1884, a rhizostome Scyphomedusa. Bulletin of the Southern California Academy of Science, 89, 130-136.

Larson, R.J., and D.G. Fautin, 1989. Stauromedusae of the genus Manania (=Thaumatoscyphus) (Cnidaria, Scyphozoa) in the northeast Pacific, including descriptions of new species Manania gwilliami and Manania handi. Canadian Journal of Zoology, 67:1543-1549.

Larson, R.J. and G.H. Harbison. 1990. Medusae from McMurdo Sound, Ross Sea including the descriptions of two new species, Leuckartiara brownei and Benthocodon hyalinus. Polar Biology, 11:19-25.

Larson, R.J., C.E. Mills, and G.R. Harbison. 1991. Western Atlantic midwater hydrozoan and scyphozoan medusae: in situ studies using manned submersibles. Hydrobiologia, 216/217:311-317.

Larson, R. J., G. I. Matsumoto, L. P. Madin, and L. M. Lewis. 1992. Deep-sea benthic and benthopelagic medusae: recent observations from submersibles and a remotely operated vehicle. Bulletin of Marine Science, 51:277–286.

Leonard, J.L. 1983. The effect of environmental factors on swimming activity in Sarsia tubulosa M. Sars (Hydrozoa). Mar. Behav. Physiol., 9:99-110.

Loeb, M.J. 1972. Strobilation in the Chesapeake Bay sea nettle – I. The effects of environmental temperature changes on strobilation and growth. Journal of Experimental Zoology, 180:279-292.

Lotan, A.,  L. Fishman and E. Zlotkin. 1996. Toxin compartmentation and delivery in the cnidaria: The nematocyst’s tubule as a multiheaded poisonous arrow.  Journal of Experimental Zoology, 275(6):444-451.

Lucas, C.H. 2001. Reproduction and life history strategies of the common jellyfish, Aurelia aurita, in relation to its ambient environment.  Hydrobiologia 451 (Developments in Hydrobiology, 155):229-246. 

Lucas, C.H., A.G. Hirst and J A. Williams. 1997. Plankton dynamics and Aurelia aurita production in two contrasting ecosystems: comparisons and consequences. Estuarine, Coastal and Shelf Science, 45(2):209-219. 

Lucas, C.H.and S. Lawes. 1998. Sexual reproduction of the scyphomedusa Aurelia aurita in relation to temperature and variable food supply. Marine Biology, 131(4):629-638.

Mackie, G. O. 1959. The evolution of the Chondrophora (Siphonophora – Disconanthae); New evidence from behavioral studies. Transactions of the Royal Society Canada, Sect. V 53: 7-20. 

_____. 1960. The structure of the nervous system in Velella. Quarterly Journal of Microsc. Science, 101:119–131.

Mackie, G.O. and G.V. Mackie. 1963. Systematic and biological notes on living hydromedusae from Puget Sound. Contributions in Zoology, National Museum of Canada, Bulletin, 199:63-84.

Mackie, G. O., R. J. Larson, K. S. Larson, and L. M. Passano. 1981. Swimming and vertical migration of Aurelia aurita (L) in a deep tank. Marine Behav. Physiology, 7:321–329.

Mackie, G.O., P.R. Pugh, and J.E. Purcell. 1987. Siphonophore biology. Advances in Marine Biology, 24:97-262.

Mackie, G. O., C. L. Singla and S. A. Arkett. 1988. On the nervous system of Velella (Hydrozoa: Chondrophora). Journal of Morphology, 198: 15-24.

Mangum, C.P., M.J. Oakes and J.M. Shick. 1972. Rate – temperature responses in scyphozoan medusae and polyps. Marine Biology, 15:298-303.

Mapstone, G.M. 1998. Bargmannia lata, an undescribed physonect siphonophore (Cnidaria, Hydrozoa) from Canadian Pacific waters. Zoologische Verhandelingen, 323:141-147.

Margulis, R.Y. 1994. Revision of the genus Rosacea (Cnidaria, Siphonophora, Calycophorae, Prayidae, Prayinae). Hydrobiological Journal, 31:33-50. Translation of Zoologicheskii Zhurnal, 73:15-28.

Marliave, J. B. and C. E. Mills. 1993. Piggyback riding by pandalid shrimp larvae on hydromedusae. Canadian Journal of  Zoology, 71: 257-263.

Martin, J.W. and H. G. Kuck 1991.  Faunal associates of an undescribed species of Chrysaora (Cnidaria, Scyphozoa) in the Southern California Bight, with notes on unusual occurrences of other warm water species in the area. Bulletin of the Southern California Academy of Sciences, 90(3): 89-101.

Martin, J.W., L.A. Gershwin, J.W. Burnett, D.G. Cargo and D.A. Bloom. 1997. Chrysaora achlyos, a
remarkable new species of scyphozoan from the eastern Pacific.  Biological Bulletin, Marine Biological Laboratory, Woods Hole, 193(1):8-13.

Martin, V.J. 2002. Photoreceptors of cnidarians. Canadian Journal of Zoology, 80:1703–1722.

_____. 2004. Photoreceptors of cubozoan jellyfish. Hydrobiologia, 530-531(1):135-144.

_____. and R. Koss. 2002. Phylum Cnidaria. Pp. 51–108 in Atlas of Marine Invertebrate Larvae, C. M. Young, ed. Academic Press, San Diego, CA.

Martinussen, M.B. and U. Båmstedt. 2001. Digestion rate in relation to temperature of two gelatinous planktonic predators. Sarsia: 86:21-35.

Masilamoni, J. G., K. S. Jesundoss, K. Nandakumar, K. K. Satpathy, K. V. K. Nair, and J. Azariah. 2000. Jellyfish ingress: a threat to the smooth operation of coastal power plants. Curr. Sci. (Bangalore) 79:567–569.

Matanoski, J.,  R. Hood, and J. Purcell. 2001. Characterizing the effect of prey on swimming and feeding efficiency of the scyphomedusa Chrysaora quinquecirrha. Marine Biology, 139(1):191-200.

Matsumoto, G.I. 1995. Observations on the anatomy and behavior of the cubozoan Carybdea rastonii Haacke. Marine and Freshwater Behaviour and Physioliolgy, 26:139-148. 

Mayer, A.G. 1910. Medusae of the world. Scyphomedusae III. Carnegie Institution, Washington, D.C. 

_____. 1912. Temperature reactions of medusae. Science, N.S.35.

McClary, A. 1959. The effect of temperature on growth and reproduction in Craspedacusta sowerbii. Ecology, 40(1):158-162.

McDermott, J. J., P. L. Zubkoff, et al. 1982. The occurrence of the anemone Peachia parasitica as a symbiont in the scyphozoan Cyanea capillata in the lower Chesapeake Bay. ESTUARIES, 5(4): 319-321.

McGrath, D. 1985. The By-The-wind-sailor Velella velella Coelenterata Hydrozoa in Irish Waters 1976-1984. Irish Naturalists’ Journal, 21: 479-484.

_____., D. Minchin and D. Cotton. 1994. Extraordinary occurrences of the By-The-wind-sailor Velella velella (L.) (Cnidaria) in Irish Waters in 1992. Irish Naturalists’ Journal, 24: 384-426.

McHenry, M.J. and J. Jed. 2002. The ontogenetic scaling of hydrodynamics and swimming performance in jellyfish (Aurelia aurita). Journal of Experimental Biology, 206:4125-4137.

Meech, R.W. 2004. Impulse conduction in the jellyfish Aglantha digitale. Hydrobiologia, 530(1):81-89.

Mianzan, H.W. and P.F.S. Cornelius. 1999. Cubomedusae and Scyphomedusae. Pages 513-559 in D.
Boltovskoy, editor. South Atlantic zooplankton. Backhuys Publishers, Leiden, The Netherlands. 

_____, M. Pajaro, G.A. Colombo and A. Madirolas. 2001. Feeding on survival-food: gelatinous zooplankton as a source of food for anchovies. Hydrobiologia 451 (Developments in Hydrobiology, 155):1-9. 

Miglietta, M. P., L. Della Tommasa, F. Denitto, C. Gravili, P. Pagliara, J. Bouillon, and F. Boero. 2000. Approaches to the ethology of hydroids and medusae (Cnidaria, Hydrozoa). Scientia Marina, 64:63–71.

Mills, C.E., 1981. Seasonal occurrence of planktonic medusae and ctenophores in the San Juan Archipelago (NE Pacific). Wasmann Journal of Biology, 39:6-29.

______. 1981. Diversity of swimming behaviors in hydromedusae as related to feeding and utilization of space. Marine Biology, 64: 185-189.

_____. 1983. Vertical migration and diel activity patterns of hydromedusae: studies in a large tank. Journal of Plankton Research, 5:619–635.

______. 1987. In situ and shipboard studies of living hydromedusae and hydroids: preliminary observations of life cycle adaptations to the open ocean. Pp. 197-207 In Modern Trends in the Systematics, Ecology and
Evolution of Hydroids and Hydromedusae. J. Bouillon, F. Boero, F. Cicogna and P.F.S. Cornelius (eds.). Clarendon Press, Oxford.

______. 1996. Keys to the Hydrozoan Medusae (pp. 32-44, 487-489), Siphonophora (pp. 62-65, 489), Scyphozoa: Semaeostomae (pp. 65-67) and Stauromedusae (p 489). In Marine Invertebrates of the Pacific Northwest. E.N. Kozloff (ed.). University of Washington Press, Seattle.

_____. 2000. The life cycle of Halimedusa typus with discussion of other species closely related to the family Halimedusidae (Hydrozoa, Capitata, Anthomedusae). Scientia Marina, 64 (supplement 1):97-106.

_____. 2001. Jellyfish blooms: are populations increasing globally in response to changing ocean conditions?  Hydrobiologia 451 (Developments in Hydrobiology, 155):1-9. 

_____, R.J. Larson and M.J. Youngbluth. 1987. A new species of coronate scyphomedusa from the Bahamas, Atorella octogonos. Bulletin of Marine Science, 40:423-427. 

_____ and F. Sommer. 1995. Invertebrate introductions in marine habitats: two species of hydromedusae (Cnidaria) native to the Black Sea, Maeotias inexspectata and Blackfordia virginica, invade San
Francisco Bay. Marine Biology, 122:279-288.

_____ and J. Rees. 2000. New observations and corrections concerning the trio of invasive hydromedusae Maeotias marginata (= M. inexpectata), Blackfordia virginica, and Moerisia sp. in the San Francisco estuary. Scientia Marina, 64 (supplement 1):151-155.

Mills, C. E., F. Boero, A. Migotto, and J. M. Gili, eds. 2000. Trends in Hydrozoan Biology-IV, Scientia Marina, 64 (Supl. 1).

Miyake, H., M. Terazaki, and Y. Kakinuma. 2002. On the polyps of the common jellyfish Aurelia aurita in Kagoshima Bay. Journal of Oceanography, 58(3):451-459.

Morandini, A.C. and F.L. da Silveira. 2001. Sexual reproduction of Nausithoë aurea (Scyphozoa, Coronatae). Gametogenesis, egg release, embryonic development and gastrulation. Scientia Marina, 65(2):139-149.

Morandini, A.C. and A.C. Marques. 2010. Revision of the genus Chrysaora Péron & Lesueur, 1810 (Cnidaria: Scyphozoa). Zootaxa, 2464:1-97.

Müller, W.A. and T. Leitz. 2002. Metamorphosis in cnidaria. Canadian Journal of Zoology, 80: 1755–1771.

Mutlu, E. 2001. Distribution and abundance of moon jellyfish (Aurelia aurita) and its zooplankton food in the Black Sea.  Marine Biology, 138(2):329-339.

Nagai, T.,  Y. Watarai, and N. Suzuki. 2001. Characterization of β-N-Acetylhexosaminidase from rhizostomous jellyfish, Rhopilema asamushi, mesogloea. Fish Physiology and Biochemistry, 25(1):53-59.

Naumov, D. V. 1969. Hydroids and hydromedusae of the USSR (J. Salkind, Israel Program for Scientific Translations, Trans.). Israel Program for Scientific Translations, Jerusalem, 660 pp.

Neumann, R., G. Schmahl, and D.K. Hofmann. 1980. Bud formation and control of polyp morphogenesis in Cassiopea andromeda (Scyphozoa).  In: P. Tardent and R. Tardent (Eds.) Developmental and Cellular Biology of Coelenterates, 217-223, Elsevier/North-Holland Biomedical Press.

Nielsen, A.S., A.W. Pedersen and H.U. Riisgaard. 1997.  Implications of density driven currents for interaction between jellyfish (Aurelia aurita) and zooplankton in a Danish fjord. Sarsia, 82(4):297-305.

Olesen, N.J. 1995. Clearance potential of jellyfish Aurelia aurita, and predation impact on zooplankton in a shallow cove. Marine Ecology Progress Series, 124:63-72.

Olesen N.J., J.E. Purcell and D.K. Stoecker. 1996. Feeding and growth by ephyrae of scyphomedusae Chrysaora quinquecirrha. Marine Ecology Progress Series, 137:149-159. 

Olmon, J. E. and K. L. Webb. 1974. Metabolism of 131I in relation to strobilation of Aurelia aurita L.
(Scyphozoa). Journal of Experimental Marine Biology and Ecology, 16:113–122.

Omori, M. and E. Nakano. 2001. Jellyfish fisheries in southeast Asia.  Hydrobiologia 451 (Developments in
Hydrobiology, 155):1-9. 

Omori, M. and M. Kitamura. 2004. Taxonomic review of three Japanese species of edible jellyfish (Scyphozoa: Rhizostomeae). Plankton Biol. Ecol., 51(1):36-51.

Ostman, C. 1997. Abundance, feeding behaviour and nematocysts of scyphopolyps (Cnidaria) and nematocysts in their predator, the nudibranch Coryphella verrucosa (Mollusca). Hydrobiologia, 355(1-3):21-28.

Ostman, C. and J. Hydman. 1997. Nematocyst analysis of Cyanea capillata and Cyanea lamarckii (Scyphozoa, Cnidaria).  Scientia Marina, 61(3):313-344.

Pages, Francesc. 2000. Biological associations between barnacles and jellyfish with emphasis on the ectoparasitism of Alepas pacifica (Lepadomorpha) on Diplulmaris malayensis (Scyphozoa). Journal of Natural History, 34:2045-56.

Panteleeva, N.N., E.A. Frolova and O.V. Sheiko. 1999.  New records of the benthic medusa Ptychogastria polaris Allman, 1878 (Trachylida, Hydroidea) in the Barents Sea and off the Kurile Islands (Pacific Ocean). Polar Biology, 22(6):372-378.

Pearse, J.S. and V.B. Pearse. 1978. Vision in cubomedusan jellyfishes. Science, 199: 458.

Petersen, K.W. 1990. Evolution and taxonomy in capitate hydroids and medusae (Cnidaria: Hydrozoa). Zoological Journal of the Linnean Society, 100:101-231.

Piatigorsky, J., J. Horwitz, et al. 1989.  The cellular eye lens and crystallins of cubomedusan jellyfish.  Journal of Comparative Physiology, 164(5): 577-588.

Pitt, K.A. 2000. Life history and settlement preferences of the edible jellyfish Catostylus mosaicus (Scyphozoa: Rhizostomeae).  Marine Biology, 136(2):269-279.

Pitt, K.A. and M.J. Kingsford. 2000. Reproductive biology of the edible jellyfish Catostylus
mosaicus
(Rhizostomeae). Marine Biology, 137(5/6):791-799.

Pitt, K.A. and M.J. Kingsford. 2000. Geographic separation of stocks of the edible jellyfish, Catostylus mosaicus (Rhizostomeae) in New South Wales, Australia. Marine Ecology Progress Series, 196:143-155.

Pugh, P.R. 1992a. A revision of the sub-family Nectopyramidinae (Siphonophora, Prayidae). Philosophical Transactions of the Royal Society of London (B), 335:281-322.

_____. 1992b. The status of the genus Prayoides (Siphonophora: Prayidae). Journal of the Marine Biological Association of the United Kingdom, 72:895-909.

_____. 1992c. Desmophyes haematogaster, a new species of prayine siphonophore (Calycophora, Prayidae). Bulletin of Marine Science, 50:89-96.

_____. 1998. A re-description of Frillagalma vityazi Daniel 1966 (Siphonophorae, Agalmatidae). Scientia Marina, 62:233-245.

_____. 1999. A review of the genus Bargmannia Totton, 1954 (Siphonophorae, Physonecta, Pyrostephidae). Bulletin of the Natural History Museum, London (Zoology Series), 65:51-72.

Pugh, P.R. and G.R. Harbison. 1987. Three new species of prayine siphonophore (Calycophorae, Prayidae) collected by submersible, with notes on related species. Bulletin of Marine Science, 41:68-91.

Pugh, P.R. and F. Pages. 1995. Is Lensia reticulata a diphyine species (Siphonophora, Calycophora, Diphyidae)? A re-description. Scientia Marina, 59:181-192.

Pugh, P.R. and M.J. Youngbluth. 1988a. Two new species of prayine siphonophore (Calycophorae, Prayidae) collected by the submersibles Johnston-Sea-Link I and II. Journal of Plankton Research, 10:637-657.

_____. 1988b. A new species of Halistemma (Siphonophora, Physonectae, Agalmidae) collected by submersible. Journal of the Marine Biological Association of the United Kingdom, 68:1-14.

Purcell, J.E. 1980. Influence of siphonophore behavior on their natural diets; evidence for aggressive mimicry. Science, 209:1045-1047. 

_____. 1981. Selective predation and caloric consumption by the siphonophore Rosacea cymbiformis in nature. Marine Biology, 63:283-294. 

_____. 1981. Dietary composition and diel feeding patterns of epipelagic siphonophores. Marine Biology, 65:83-90.

Purcell, J.E. and J.H. Cowan. 1995. Predation by the scyphomedusan Chrysaora quinquecirrha on Mnemiopsis leidyi ctenophores. Marine Ecology Progress Series, 129:63-70. 

Purcell, J.E,  J.R. White, D.A. Nemazie and D.A. Wright. 1999. Temperature, salinity and food effects on asexual reproduction and abundance of the scyphozoan Chrysaora quinquecirrha.  Marine Ecology Progress Series, 180:187-196.

Purcell, J.E., U. Bamstedt and A. Bamstedt. 1999. Prey, feeding rates, and asexual reproduction rates of the introduced oligohaline hydrozoan Moerisia lyonsi.  Marine Biology, 134(2):317-325.

Purcell, J.E., et. al. 2000. Aggregations of the jellyfish Aurelia labiata: abundance, distribution, association with age-0 walleye pollock, and behaviors promoting aggregation in Prince William Sound, Alaska, USA. Marine Ecology Progress Series, 195:145-158.

Purcell, J.E. and M. N. Arai. 2001. Interactions of pelagic cnidarians and ctenophores with fish: a review.
Hydrobiologia 451 (Developments in Hydrobiology, 155):1-9.

Purcell, J.E., W.M. Graham, and H.J. Dumont (Eds.). 2001. Jellyfish blooms: ecological and societal importance. Kluwer Academic Publishers, Dordrecht, the Netherlands.

Purcell, J.E. and M.V. Sturdevant. 2001. Prey selection and dietary overlap among zooplanktivorous jellyfish and juvenile fishes in Prince William Sound, Alaska.  Marine Ecology Progress Series, 210:67-83.

Radwan, F., L. Gershwin and J. Burnett. 2000. Toxilogical studies on the nematocyst venom of Chrysaora achlyos. Toxicon, 38: 1581-1591.

Rahat, M. and O. Adar. 1980. Effect of symbiotic zooxanthellae and temperature on budding and strobilation in Cassiopeia andromeda. Biological Bulletin (Woods Hole), 159:394-401.

Rahat, M. and D.K. Hofmann. 1987.  Bacterial and algal effects on metamorphosis in the life-cycle of Cassiopea andromedaAnnals of the New York Academy of Sciences, 503:449-458.

Raikova, E.V. 1994. Life cycle, cytology, and morphology of Polypodium hydriforme, a coelenterate parasite of the eggs of acipensieriform fishes. Journal of Parasitology, 80:1-22.

Ralph, P.M. 1960. Tetraplatia, a coronate scyphomedusan. Proceedings of the Royal Society, Series B, 152:263-281.

Raskoff, K.A. 2001. The impact of El Nino events on populations of mesopelagic hydromedusae.  Hydrobiologia 451 (Developments in Hydrobiology, 155):121-129.

_____. 2002. Foraging, prey capture, and gut contents of the mesopelagic narcomedusa, Solmissus (Cnidaria, Hydrozoa). Marine Biology, 141:1088–1107.

Rees, J. T. 1979. Laboratory and field studies on Eutonina indicans (Coelenterata: Hydrozoa), a common
leptomedusa of Bodega Bay, California. Wasmann Journal of Biology, 36:201–209.

_____. 2000. A pandeid hydrozoan, Amphinema sp., new and probably introduced to central California: life history, morphology, distribution, and systematics. Scientia Marina, 64 (supplement 1):165-172. 

Rees, J. T. and R.J. Larson. 1980. Morphological variation in the hydromedusa genus Polyorchis on the west coast of North America. Canadian Journal of Zoology, 58, 2089-2095.

Rees, J.T. and L.A. Gershwin. 2000. Non-indigenous hydromedusae in California’s upper San Francisco Estuary: life cycles, distribution, and potential environmental impacts. Scientia Marina, 64 (supplement 1):73-86. 

Rees, W. J. and F. S. Russell. 1937. On rearing the hydroids of certain medusae, with an account of the methods used. Journal of the Marine Biological Association UK, 22:61–82.

Robison, B. H., K. R. Reisenbichler, R. E. Sherlock, J. M. B. Silguero, and F. P. Chavez. 1998. Seasonal abundance of the siphonophore, Nanomia bijuga, in Monterey Bay. Deep-Sea Research II, 45:1741–1751.

Rogers, C.A., D.C. Biggs, and R.A. Cooper. 1978. Aggregation of the siphonophore Nanomia cara in the Gulf of Maine: observations from a submersible. Fisheries Bulletin, 76: 281–284.

Russell, F.S. 1953. The Medusae of the British Isles: Anthomedusae, Leptomedusae, Limnomedusae, Trachymedusae and Narcomedusae. Cambridge University Press, Cambridge, 530 pp., 35 pls.

_____. 1959. A viviparous deep-sea jellyfish. Nature,1527-1529.

______. 1970. The Medusae of the British Isles. II. Pelagic Scyphozoa. Cambridge University Press, Cambridge, 284 pp.

_____. and W. J. Rees. 1960. The viviparous scyphomedusa Stygiomedusa fabulosa Russell. Journal of the Marine Biological Association U.K., 39:303-317.

Satterlie, R.A. 1979. Central control of swimming in the cubomedusan Carybdea rastonii. Journal
of  Comparative Physiology,  133:357-367.

_____.  1985.  Putative extraocular photoreceptors in the outer nerve ring of Polyorchis penicillatus. Journal of Experimental Zoology, 233:133-137.

_____. 2002. Neuronal control of swimming in jellyfish: a comparative story. Canadian Journal of Zoology, 80:1654–1669.

Schaadt, M. S. 1993. Joining the jelly revolution on a shoestring budget. Third International Aquarium Congress (Boston): 262-264.

Schaadt, M., L.Yasukochi, L. Gershwin and D. Wrobel. 2001. Husbandry of the black jelly (Chrysaora achlyos), a newly discovered scyphozoan in the eastern North Pacific Ocean. Bulletin de l’Institut Oceanographique, Monaco Special 20(fasc. 1): 289-296.

Schmahl, G. 1985. Bacterially induced stolon settlement in the scyphopolyp of Aurelia aurita (Cnidaria,
Scyphozoa). Helgol. Meeresunters., 39:33–42.

Schneider, G. and G. Behrends. 1994. Population dynamics and the trophic role of Aurelia aurita medusae in the Kiel Bight and western Baltic. ICES Journal of Marine Science, 51(4):359-367.

Schubert, P. 1996. The marine Fauna of New Zealand: athecate hydroids and their medusae (Cnidaria: Hydrozoa). New Zealand Oceanographic Institute Memoirs, 106:1-159. 

Schuyler, Q. and B.K. Sullivan. 1997.  Light responses and diel migration of the scyphomedusa Chrysaora
quinquecirrha
in mesocosms. Journal of Plankton Research, 19(10):1417-1428.

Segura-Puertes, L. 1984. Morphology, systematics and zoogeography of medusae (Cnidaria: Hydrozoa and Scyphozoa) from the eastern tropical Pacific. Inst. Cienc. del Mar y Limnol. Univ. Nal. Auton. Mexico Publ. Esp., 8:1-320.

Sherlock, R.E. and B.H. Robison. 2000. Effects of temperature on the development and survival of Nanomia bijuga (Hydrozoa, Siphonophora). Invertebrate Biology, 119(4):379-385.

Shimomura, O., et al. 2001. Isolation and properties of the luciferase stored in the ovary of the scyphozoan medusa Periphylla periphylla. Biological Bulletin, 210:339-347. 

Siefker, B., M. Kroiher and S. Berking. 2000. Induction of metamorphosis from the larval to the polyp stage is similar in Hydrozoa and a subgroup of Scyphozoa (Cnidaria, Semaeostomeae). Helgoland Marine Research, 54(4):230-236.

da Silveira, F.L. and A.C. Morandini.  1998.  Asexual reproduction in Linuche unguiculata (Swartz, 1788) (Scyphozoa: Coronatae) by planuloid formation through strobilation and segmentation. Proceedings of the Biological Society of Washington, 111(4): 781-794.

Skogsberg, T. 1948. A systematic study of the Family Polyorchidae (Hydromedusae). Proceedings of the California Academy of Sciences, Fourth Series, 26(5):101-124.

Soares Moreira, G. 1978. A preliminary laboratory study on the salinity and temperature tolerances of some medusae from the Sao Paulo coast, Brazil. Bolm Inst. Oceanogr., Sao Paulo, 27(2):45-55.

Sommer, F. 1986. Methods for culture and display of the moon jelly, Aurelia aurita. American Association of Zoological Parks and Aquariums Regional Conference Proceedings, Western Regional Conference, Tacoma, WA.

_____. 1992a. Advances in culture and display of Aurelia aurita, the moon jelly. American Association of Zoological Parks and Aquariums Regional Conference Proceedings: 391-396.

_____. 1992b. Husbandry aspects of a jellyfish exhibit at the Monterey Bay Aquarium. Pp. 362–369 in American Associations of Zoological Parks and Aquariums Annual Conference Proceedings, Toronto.

_____. 1993. Jellyfish and beyond: husbandry of gelatinous zooplankton at the Monterey Bay Aquarium. Pp. 249–261 in Proceedings of the Third International Aquarium Congress, Boston, MA.

Soong, K. and L.C. Cho. 1998. Synchronized release of medusae from three species of hydrozoan fire corals. Coral Reefs, 17(2):145-154.

Spadinger, R. and G. Maier. 1999. Prey selection and diel feeding of the freshwater jellyfish, Craspedacusta sowerbyi. Freshwater Biology, 41(3):567-573.

Spangenberg, D. B. 1964. New observations on Aurelia. Transactions American Micro. Society, 83:448-455, pl. I-II.

_____. 1965a. Cultivation of the life stages of Aurelia aurita under controlled conditions. Journal of
Experimental Zoology, 159:303–318.

_____. 1965b. A study of strobilation in Aurelia aurita under controlled conditions. Journal of Experimental Zoology, 160:1-10.

_____. 1967. Iodine induction of metamorphosis in Aurelia. Journal of Experimental Zoology, 165:441-450.

_____. 1968. Recent studies of strobilation in jellyfish. Oceanography Marine Biology Annual Review, 6:231-247.

_____. 1971. Thyroxine induced metamorphosis in Aurelia. Journal of Experimental Zoology, 178:183–194.

_____. 1974. Thyroxine in early strobilation in Aurelia. American Zoologist, 14:825-831.

Spangenberg, D.B., F.A. Lattanzio, and G. Navarro. 2004. Methionine and gold chloride alleviate adverse effects of glutamate on motility of ephyrae of Aurelia aurita (Linnaeus, 1758) (Scyphozoa: Semaeostomeae). Hydrobiologia, 530-531(1):355-363. 

Sparks, C., et al. 2001. Observations on the distribution and relative abundance of the scyphomedusan Chrysaora hysoscella (Linne, 1766) and the hydrozoan Aequorea aequorea (Forskal, 1775) in the northern Benguela ecosystem.  Hydrobiologia 451 (Developments in Hydrobiology, 155):275-286. 

Spencer, A.N.  1978. Neurobiology of Polyorchis  I. Function of effector systems. Journal of Neurobiology,  9:143-157.

Spencer, A.N.  1982.  The physiology of a coelenterate neuromuscular synapse. Journal of Comparative
Physiology, 148: 353-363.

Stanley, G. D., Jr. and T. E. Yancey. 1986. A new late Paleozoic chondrophorine (Hydrozoa, Velellidae) by-the-wind sailor from Malaysia. Journal of Paleontology, 60: 76-83.

Strand, S.W. and W.M. Hamner. 1988. Predatory behavior of Phacellophora camtschatica and size-selective predation upon Aurelia aurita (Scyphozoa: Cnidaria) in Saanich Inlet, British Columbia. Marine Biology, 99:409-414.

Stepanjants, S.D., A.L. Lobanov, and M.B. Dianov. 1999. New approaches to the search for interspecies diagnostic differences within the genus Obelia. Analysis of growth and development of free medusae of Obelia spp. from different areas of the world Ocean (under laboratory conditions). Zoosystematica Rossica Suppl., No. 1:34-50. 

Stretch, J.J., and J.M. King. 1980. Direct fission: an undescribed reproductive method in hydromedusae. Bulletin of Marine Science, 30:522-525.

Suarez-Morales, E.,  L. Segura-Puertas and R. Gasca.  1999.  Medusan (Cnidaria) assemblages off the Caribbean Coast of Mexico.  Journal of Coastal Research, 15(1):140-147.

Suchman, C.L. and B.K. Sullivan. 1998. Vulnerability of the copepod Acartia tonsa to predation by
the scyphomedusa Chrysaora quinquecirrha: Effect of prey size and behavior. Marine Biology, 132(2):237-245.

Suchman, C. L. and B. K. Sullivan. 2000. Effect of prey size on vulnerability of copepods to predation by the
scyphomedusae Aurelia aurita and Cyanea sp. Journal of Plankton Research, 22:2289–2306.

Sugiura, Y. 1965. On the life history of rhizostome medusae. III. On the effects of temperature on the strobilation of Mastigias papua. Biological Bulletin (Woods Hole), 128:493-496.

Sullivan, B.K., C.L. Suchman and J.H. Costello. 1997.  Mechanics of prey selection by ephyrae of the scyphomedusa Aurelia aurita.  Marine Biology, 130(2):213-222.

Tamburri, M. N., M. N. Halt, and B. H. Robison. 2000. Chemically regulated feeding by a midwater medusa. Limnology and Oceanography, 45:1661–1666.

Thieme, C. and D.K. Hofmann. 2003. An endogenous peptide is involved in internal control of metamorphosis in the marine invertebrate Cassiopea xamachana (Cnidaria: Scyphozoa). Dev. Genes Evol., 213:97-101.

_____. 2003. Control of head morphogenesis in an invertebrate’s asexually produced larva-like bud (Cassiopea andromeda; Cnidaria: Scyphozoa). Dev. Genes Evol., 213:127-133.

Thomas, L. 1963. Phyllosoma larvae associated with medusae. Nature, 198: 208.

Thuesen, E.V. 1993. Vampyrocrossota childressi, a new genus and species of black medusa from the bathypelagic zone off California (Cnidaria: Trachymedusae: Rhopalonematidae). Proceedings of the Biological Society of Washington, 106(1):190-194.

_____ and J.J. Childress. 1994. Oxygen consumption rates and metabolic enzyme activities of oceanic California medusae in relation to body size and habitat depth. Biological Bulletin, 187:84-98.

Torrey, H.B. 1909. The Leptomedusae of the San Diego Region. University of California Publications in Zoology, 6:11-31.

Totton, A.K. 1965a. A Synopsis of the Siphonophora. Trustees of the British Museum (Natural History), London, 230 pp, 40 pls.

_____. 1965b. A new species of Lensia (Siphonophora: Diphyidae) from the coastal waters of Vancouver, B.C., and its comparison with Lensia achilles Totton and another new species Lensia cordata. Annals and Magazine of Natural History (13)8:71-76.

Tsien, R.Y. 1998. The green fluorescent protein. Annual Review of Biochemistry, 67:509-544.

Uchida, T. 1929. Studies on the Stauromedusae and Cubomedusae, with special reference to their metamorphosis. Japanese Journal of Zoology, 2:103-193.

Ueno, S., C. Imai and A. Mitsutani. 1997. Statolith formation and increment in Carybdea rastoni: evidence of synchronization with semilunar rhythms.  Proceedings of the 6th International Conference on coelenterate
biology, ed. Den Hartog, pp. 491-496.

Utter, B. D. 2001. Culturing the umbrella jelly, Eutonina indicans (Romanes, 1876). Drum and Croaker 32:
38–44.

Vader, W. 1972. Associations between gammarid and caprellid amphipods and medusae. Sarsia, 50:51-56. 

Verde, E.A. and L.R. McCloskey. 1998.  Production, respiration, and photophysiology of the mangrove
jellyfish Cassiopea xamachana symbiotic with zooxanthellae: Effect of jellyfish size and season.  Marine Ecology Progress Series, 168:147-162.

Watanabe, T. and H. Ishii. 2001. In situ estimation of ephyrae liberated from polyps of Aurelia aurita
using settling plates in Tokyo Bay, Japan.  Hydrobiologia 451 (Developments in Hydrobiology, 155):247-258. 

Werner, B. 1973. New investigations on the systematics and evolution of the class Scyphozoa and the phylum Cnidaria. Publications Seto Marine Biology Laboratory, 20: 35–61.

Williams, E. H., Jr., L. Bunkley-Williams, C.G. Lilyestrom, R.J. Larson, N.A. Engstrom, E.A.R. Ortiz-Corps, and J.H. Timber. 2001. A population explosion of the rare tropical/subtropical purple sea mane, Drymonema dalmatinum, around Puerto Rico in the summer and fall of 1999. Caribbean Journal of Science, 37(1-2): 127-130.

Wittenberg, J. B. 1960. The source of carbon monoxide in the float of the Portuguese man-of-war, Physalia physalis L. Journal of Experimental Biology, 37: 698-705.

Woodcock, A.H. 1997.  Why sailing sea animals have mirror images.  Pacific Science, 51(1):12-17.

Yanagihara, A.A., J.M.Y. Kuroiwa, and D.D. Kunkel. 2002. Ultrastructural characterization of nematocysts from the Hawaiian box jellyfish (Carybdea alata).  Cell and Tissue Research, 308:307-318.

Yanagihara, A.A., J.M.Y. Kuroiwa, L. Oliver, and D.D. Kunkel. 2002. The ultrastructure of nematocysts from the fishing tentacle of the Hawaiian bluebottle, Physalia utriculus (Cnidaria, Hydrozoa, Siphonophora).  Hydrobiologia, 489:139-150.

Yamamoto, T., J. Hiromi, J. Kinoshita and S. Kadota. 1996. Effect of food condition upon the growth and survival in early developmental stages of scyphomedusa, Aurelia aurita. Bulletin of the College of Agriculture and Veterinary Medicine Nihon University, 53:79-82.

Yasuda, T. 1969. Ecological studies on the jellyfish, Aurelia aurita in Urazoko Bay, Fukui Pref. – III. Growth. The Aquaculture, 17(3):145-154.

Youngbluth, M.J. and U. Bamstedt. 2001. Distribution, abundance, behavior and metabolism of Periphylla periphylla, a mesopelagic coronate medusa in a Norwegian fjord.  Hydrobiologia 451
(Developments in Hydrobiology, 155):321-333. 

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Tetraplatia

Tetraplatia volitans Busch, 1851
Phylum Cnidaria / Class Scyphozoa / Order Coronatae / Family Tetraplatidae
tetraplatia

Even a jellyfish expert may be thrown off by this bizarre little creature – it hardly resembles any other jellyfish. Looking more like a worm, and being 4 to 9 mm long, it’s easily overlooked. It feeds on small zooplankton, capturing prey without the aid of tentacles, which are lacking. The color is whitish to bluish white. The body is cylindrical with pointed ends, with a constriction closer to the aboral end. Its cnidarian affinities are revealed by the presence of nematocysts contained in 4 tracks that run the length of the body, and 4 shorter tracks between these. The coronal groove is divided into 8 pairs of lappet-like structures. Between the lappets are marginal sense structures (8 total). The four gonads are not easily visible. Tetraplatia is cosmopolitan, found worldwide in oceanic waters, from the surface down to about 900 meters.

All images in the JelliesZone © David Wrobel and may not be copied or used in any form without permission.

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Chrysaora colorata

pelagia4
pelagia3
pelagia
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Purple-stripe jelly, Chrysaora colorata, Monterey CA, Pacific Ocean
pelagiacrabs

Of all the gelatinous creatures visiting Monterey Bay, the purple-striped jelly is certainly among the most recognizable and spectacular. Based on certain morphological characters, a taxonomic revision has placed this species (formerly Pelagia colorata) in the genus Chrysaora. With a bell of up to 70 cm diameter, usually streaked with a radial pattern of stripes, and long, flowing oral arms, this jelly is quite impressive. The four frilly oral arms have a coiled appearance. Eight marginal tentacles alternate with eight sensory rhopalia. The tentacles are well armed with nematocysts and can produce a relatively painful sting. Although large specimens are typically endowed with very distinct purple pigment patterns, younger individuals have a pale pinkish bell that lacks the dramatic stripes and patterns of adults. Youngsters also have long, thin, dark maroon tentacles that assume a more subdued coloration by adulthood. Young adults like the one in the second photo can be endowed with truly impressive oral arms, sometimes as long as 4 to 5 meters. Very old individuals often lack the long flowing oral arms and have thickened, pale tentacles. The photos here show a progression from a jelly toddler to a withered old-timer.

Unlike sea nettles and moon jellies, purple-striped jellies are not seen in large surface aggregations. Juvenile slender crabs (Cancer gracilis, bottom photo) often make homes of this jelly and travel with their host until ready to assume a benthic existence. A wide variety of zooplankton serve as prey, including copepods, larval fish, ctenophores, salps, other scyphomedusa, and fish eggs. Chrysaora colorata has a relatively limited range primarily off the coast of California. It is possible to establish polyps and culture this species in captivity, although it’s not as easy as some other species. When provided appropriate aquarium conditions (such as a kreisel tank), the medusae do well under captive conditions. Purple-striped jellies are a popular species for display at public aquariums, but cultured individuals never attain the spectacular dimensions or coloration of their wild counterparts.

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Physophora

Physophora hydrostatica Forskal, 1775
Phylum Cnidaria / Class Hydrozoa / Subclass Siphonophorae / Order Physonecta / Family Physophoridae
Physonect siphonophore, Physophora hydrostatica, Point Lobos CA, Pacific Ocean
physophora2

This stunning physonect siphonophore is easily distinguished from any other gelatinous West Coast animal. A conspicuous silvery apical gas-filled float is followed by a set of swimming bells that occupy about half the length. Finger-like dactylozooids, colored with beautiful tinges of orange and violet, attach at the base of the swimming bells. These structures house relatively potent nematocysts that can impart a strong sting on those careless enough to make contact. A mass of feeding gastrozooids and reproductive gonozooids lie inside the ring of dactylozooids. Typical length of the compact swimming bell / dactylozooid portion of the siphonophore is from 8 to 12 cm. Trailing behind are the highly extensible tentacles that usually exceed the length of the rest of the siphonophore. Physophora typically swims slowly with tentacles extended as it drifts for zooplankton prey. Look carefully at the whitish clumps spaced at regular intervals along the tentacles. They resemble swimming copepods as the tentacles are repeatedly contracted and extended. Perhaps this is a method for luring copepod-seeking predators that instead become prey for the siphonophore. Physophora is occasionally seen in surface waters of central California, but never in any great numbers.

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