|This is a small phylum with
fewer than 100 known species divided into two Classes. They are all marine and
mainly found in warm waters. Most species are small, but some can grow up to 2 m long. Their common name, "comb jellies", comes from the
eight comb rows of cilia that are used in locomotion.
They are the largest animals to use cilia for locomotion. The threads in the colloblasts wrap around the prey entangling it. They have the ability to
luminesce from chemical reactions in the gastrodermis. They have a statocyst containing a calcareous statolith which gives the animal information about its position and orientation.
All in this class have two
tentacles; a characteristic species is Hormimorpha plumosa seen
on the right. Some in this class are flattened into a ribbon-like shape along the
plane of the tentacles and have an undulatory motion. Cestium sp., above, is an example. It can grow to over 100 cm in length.
These do not have tentacles
at any stage in their lives; a characteristic species is Beroe
punctatus, above left. Another in the Beroe genus can be seen below, these can grow to 20 cm long and 5 cm wide. When found in cold waters they tend to have a pinkish tinge.