Hydras of North America

14 p. : ill. ; 24 cm.Includes bibliographical references (p. 13-14)."Hydra hymanae, new species, is a hydra of medium size, with short tentacles. It is usually found in very rapidly moving water. Its identifying characters are: column 7 to 12 mm. in length, not differentiated into body and stalk but with base bent in the form of a hook; habit of standing partly contracted, with the main portion of the column approximately parallel with the substratum; tentacles usually six in number, about one-half the length of the column, extended in drooping positions; broadly oval, large glutinants with a beak-like projection at the pointed end; unusually large penetrants and volvents; hermaphroditic; testes few, roughly hemispherical, with or without nipples; season of sexual activity October, Novemeber, December; embryo flattened and enclosed in a plano-convex, spined theca attached to the substratum; habitat occasionally still water, more often rapidly moving water. The type locality is Little Falls, New Jersey. Other localities are Verona, Delawanna, Lake Valhalla, all in New Jersey"--P. 13