At first glance, the comb jelly affinities of this ribbon-like gelatinous animal are easy to overlook.  A careful look at the edge opposite the mouth, however, reveals the distinctive comb rows.  The 8 rows lie in a pair of lines along the aboral edge.  Four of the comb rows are very short; the other 4 extend along most of the length of the comb jelly.  Cestid ctenophores have flattened bodies in the tentacular plane while greatly elongated in the pharyngeal plane.  The mouth is positioned in the central area of the leading edge, from which are attached thin tentacles.  While feeding, Velamen swims with this oral edge forward and the tentacles trailing behind over the rest of the body.  When disturbed, it has an entirely different and vigorous escape response in which the body undulates in a snake-like fashion.  The body is transparent and colorless (although may occasionally have a yellowish tint), and no more than 20 cm long.  Another cestid comb jelly, the so-called Venus' girdle (Cestum veneris), can attain much longer lengths of up to 1.5 meters.  Velamen is a cosmopolitan inhabitant of tropical and subtropical waters, and occasionally may be found in nearshore surface waters of central California.  With its transparent body, even dense aggregations are easily overlooked.  Despite their different appearances, cestid comb jellies are closely allied with the lobates, as evidenced by both having a larval cydippid stage with tentacles.

All photographs © David Wrobel and may not be used or copied without permission!

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