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Note on a Rhizocephalous crustacean from fresh water and on some specimens of the order from Indian seas

1911; Volume: 6; Linguagem: Inglês

10.5962/bhl.part.21325

0375-099X

Marine Biology and Ecology Research

My reason for describing the parasite described below is its extraordinary habitat.It was found attached to one of the type specimens (a female) of the crab Scsarma thelxinoe ina jungle stream, at an altitude of 700 feet above sea-level, near Port Blair in the Andamans and is, so far as I am aware, the only representative of the Rhizocephala as yet found anywhere but in thesea.Dr. de Man refers to it in his original description of its host as a Sacculina (Rec.Ind. Mus., ii, p. 181), but it differs considerably in structure not only from that genus but from any other hitherto described.My description, being based on a single specimen not in the best condition, must necessarily be superficial, but I hope that its publication may lead to the discovery of fresh specimens, to its amplification and to the correction of any errors it may contain.A word of warning is necessary as regards the habitat of the species.Grapsid crabs as a rule breed in brackish water if not in the sea, and it is possible that Sesarma thelxinoe, which is only known from a small oceanic island, may visit the sea periodically for that purpose, and may there become infected by the parasite.Nevertheless, the fact that the latter contains larvae in the brood-pouch while living at an altitude of 700 feet entitles it to be included in the freshwater fauna of the Indian Empire and suggests that it is able to flourish in jungle streams, even if it also occurs in the sea.As the Rhizocephala of Oriental waters have received little attention I may put on record the fact that Sacculina carcini !(sensu lato) is not uncommon on the crabs Doclea ovis and Menippe rumphii in shallow water off the coasts of Madras and Orissa and off the mouth of the R. Hughli.The Indian Museum also possesses specimens on a species of Gontosoma from Madras.The only other Rhizocephala from Indian seas in the collection are two somewhat shrivelled and distorted specimens which I attribute with little doubt to Geoffrey Smith's Triangulus munidae, although the lip of the orifice is perhaps more Erne, than his figure 1 The late Dr.