Hydroid Definition

Hydroid Sentence Examples

• The hydroid colony shows many variations in form and architec- ture which depend simply upon differences in the methods in which polyps are budded.

• In this way the hydroid colony becomes composed of two portions of different function, the nutritive " trophosome," composed of non-sexual polyps, and the reproductive " gonosome," composed of sexual medusaindividuals, which never exercise a nutritive function while attached to the colony.

• Besides the three types of individual above mentioned, there are other appendages of hydroid colonies, of which the individuality is doubtful.

• Such are the " guard-polyps " (machopolyps) of Plumularidae, which are often regarded as individuals of the nature of dactylozoids, but from a study of the mode of budding in this hydroid family Driesch concluded that the guard-polyps were not true polyp-individuals, although each is enclosed in a small protecting cup of the perisarc, known as a nematophore.

• Moreover, all the medusae budded from a given hydroid colony are either male or female, so that even the non-sexual polyp must be considered to have a latent sex.