幻のインド産カイヤドリヒドラ類

Abstract

In May of 1995 and January of 1997, at least 10 bivalve species in nine genera were surveyed for bivalve-inhabiting hydrozoans at Cochin, southwestern India. In particular, Eutima commensalis Santhakumari, 1970, for which this is the type locality, and E. japonica Uchida, 1925, a related species from Japan, were sought, since both commensals have mature medusae of like morphology. Unfortunately no hydroids were detected m any bivalve, including Perna viridis (Linnaeus, 1758) (352 specimens examined), Nausitora hedleyi Schepman (107), Martesia striata (Linnaeus, 1758) (147), Crassostrea spp. (332), Hormomya mutabilis (Gould, 1861) (15), Xenostrobus atratus (Lischke, 1871) (45), Musculista senhausia Benson, 1842 (117), Modiolus auriculatus (Krauss, 1848) (39), and Irus (Irus) mittis (Deshayes, 1854) (6). Directions for systematic research in the future are pointed out, with emphasis on clarifying the life cycles of this group of hydroids in India. Some general topics and miscellaneous observations made during the present research are also raised and discussed.