I. NOTE ON A RHIZOCEPHALOUS CRUS- 

 TACEAN FROM FRESH WATER AND 

 ON SOME SPECIMENS OF THE ORDER 

 FROM INDIAN SEAS. 



By N. ANNANDAI.E, D.Sc, F.A.S.B., Superintendent of the 

 Indian Museum. 



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 Sesarma thelxinoe in a 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 the sea. 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 

 15est 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 m 

 the sea, and it is possible that Sesarnia thelxinoe, which is only 

 known from a small oceanic island, ma}' visit the sea periodically 

 for that purpose, and may there become infected by the parasite. 

 Nevertheless, the fact that the latter contains larvae m 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 sug- 

 gests 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 avis 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 Goniosoma 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 prominent than his figure 



1 The late Dr. J. Anderson obtained a specimen on Thalamita crenata from 

 the Andamans {Proc. Zool. Soc. London, 1871, p. 144). 



