One of the more abundant gelatinous animals in Monterey Bay is this
pelagic snail. The body is almost totally transparent, with the most obvious part of
the body being the dark gut nucleus. Corolla
lacks an external shell
- an internal gelatinous pseudoconch provides skeletal support. Occasionally
the slipper-like pseudoconchs, which are covered with tubercles, are found washed up on
beaches. The large lateral oval wing-plates may have a span of up to 8 cm and flap
to maintain position or move in the water column (hence the name "sea
butterfly"). Each side possesses a row of 12 mucus
glands. Small planktonic particles are captured by a large,
delicate mucous sheet (up to 2 meters diameter) that is formed by the proboscis.
When disturbed, Corolla
swims away rapidly and usually sheds the mucous
sheet. Sea butterflies may form large surface aggregations in Monterey Bay and
other temperate waters of the Pacific Ocean. This species is the only Corolla
found off the West Coast of North America.
All photographs © David
Wrobel and may not be used or copied without permission!