Hydroids [noun]

The illustration shows a plant on which the hydroid Sertularia pumila is growing.

A hydroid about one inch high, growing in patches and appearing like tufts of moss on rocks between tide-marks.

There are some species which, having no hydroid or strobila state, mature without alternation of generation (metagenesis).

This hydroid is found creeping over seaweeds in tide-pools from Long Island Sound northward.

The hydroid Hydractinia polyclina often covers the exterior of such shells with a brown, velvety growth.

This is a branching hydroid that does not produce free medus.

Is each Hydroid of the colony an animal, and the jelly-fish another animal?

Long ago, Trembley attempted to cause, by grafting, the union of two pieces of hydroid polyps into a single individual.

All of you have seen common sea-anemones or sea-roses, and many of you will also be familiar with the so-called hydroid polyps.

In some cases both free medusae and gonophores may be produced from the same hydroid colony.