252 Records of the Indian Museum. [Vol. XXIV, 



Every large Pinna which was opened contained a pair of prawns 

 belonging either to this species or to Conchodytes biunguiculatus. 

 One pair of A. inermis was found in Pinna nigrina Lam., one pair 

 in P. vexillum Born, and the remainder in P. bicolor Gmelin.' The 

 specimens from Pamban were also obtained in Pinna. 



The species was described by Miers from a specimen obtained 

 in Pinna at Porte Molle in Queensland. It has been recorded 

 from Shark Bay, W. Australia, in Pinna (Miers) ; from the Monte 

 Bello Is., N.W. Australia, in Pinna (Rathbun) ; from Penang, 

 " taken from the infra-branchial chamber of a large Gastropod" 2 

 (Lanchester) ; from Trincomali in Ceylon (Muller) ; from the Ceylon 

 Pearl banks (Pearson) ; from the Persian Gulf Pearl banks, in Pinna 

 (Nobili) 8 ; from Dar-es-Salaam, in Pinna (Ortmann) 3 ; and, in the 

 Red Sea, from Djibouti (Nobili) 8 and Suakin Harbour, in Pinna 

 (Tattersall). 



Anchistus mirabilis (Pesta). 



191 1 .' Marygrande mirab-'lis, Pesta, Zool. Am. XXXVIII, p. 571, 



text-figs. 1-5. 

 1913. Marygrande mirabilis, Pesta, Denk. math-naturie. Kl. K Akad. 



Wiss. Wien I. XXXIX, p. 675, text-figs. 31, 32. 



Pesta appears to have confused two forms when describing 

 this species. The dactylus of the posterior legs is described and 

 figured as simple, but he includes as a variety of the same species 

 a form in which it is biunguiculate (v. Pesta, 1913, text-figs. 31^, 

 e). Judging from the species of Anchistus that I have seen it does 

 not seem possible that these two types of dactylus can be found 

 in one and the same species. * 



The form with simple dactylus is closely related to Miers' A. 

 inermis, from which, so far as can be ascertained from Pesta's 

 account, it differs only in the less depressed rostrum with apex 

 more pointed in lateral view. These characters are insufficient 

 and re-examination of Pesta' s specimens is necessary before it is 

 possible to reach any definite conclusions regarding the identity of 

 the species. That it is not synonjmious with Miers' species may 

 be inferred from the fact that it was found in the mantle-cavity of 

 Tridacna gigas, whereas A. inermis is apparently always associated 

 with Pinna. 



Pesta's specimens were obtained at Samoa. 



Anchistus gravieri, sp. nov. 



The rostrum (text-fig. 82) reaches to the end of the second 

 segment of the antennular peduncle and is directed downwards. 

 In lateral view it is rather deep, but obliquely truncate terminally 



1 1 am indebted to Dr. Baini Prashad for the identification of the species of 

 Phina. 



2 This is, I believe, the only record of a Macruran from a Gastropod and is 

 doubtless an error. 



3 Recorded as Pontonia pinnae. 



