A third specimen of the hydrozoan cnidarian Pelagohydra mirabilis Dendy, 1902, with observations on its morphology and its behaviour in the laboratory

Abstract

A live, undamaged specimen of Pelagohydra mirabilis is recorded, together with additions to the description of the morphology of both the hydroid and medusa phases. The largest medusae, which were obtained liberated in the laboratory, were ca. 3 mm in diameter and possessed up to 7 tentacles in each of 4 perradial groups. In the laboratory, the hydroid exhibited spontaneous but infrequent contractions of all of its tentacles, producing slight translatory movements through the water. Attempts are made to deduce the normal habitat of the animal. The possibility is suggested that the hydroid phase is rare in its life-history.