Polyzoa

Hydra also flourishes in this pond, but for some reasons there are few polyzoa.

Yet the echinus can have, at the best, none but the most distant genetic relationship with the Polyzoa.

More than 100 species of Polyzoa (Bryozoa) have been collected, among them are some highly interesting forms.

Vibraculum, vī-brak′ū-lum, n. one of the long whip-like appendages of the cells of some Polyzoa:—pl.

It looks likely to contain some fresh-water polyzoa, than which there are few more beautiful tenants of the water.