They are exceedingly voracious, feeding chiefly on other Ctenophora, and often swallowing animals as large as themselves.
Ctenophora, body cylindrical, moving by means of many parallel rims of cilia set in longitudinal lines on the surface.
The most important examples of such modifications are found in the Siphonophora and Ctenophora.
The Ctenophora developed later out of a branch of the latter.
The ovum of the Ctenophora is formed of an outer granular protoplasmic layer and an inner spongy mass with fatty spherules.
It is characteristic both of the Octocoralla and Hexacoralla, but is not found in the Ctenophora.
Therefore the fundamental forms become here "amphithect," as in the Ctenophora.