iqi2.] S. Kemp: Notes on Decapoda. 115 



Xiphocaridina curvirostris (Heller). 



New Zealand; Chatham Is. 

 Palaemonias ganteri (Hay). 



Mammoth cave, Kentucky. 



It is consequently a matter of some considerable interest that 

 one of these primitive Atyidae still persists in India, and the 

 identification of this species with Xiphocaridina curvirostris, 

 hitherto known only from N'ew Zealand, presents a difficult prob- 

 lem in geographical distribution. 



The material available consists of the following specimens : — 



Tezpur, Darrang District, Assam. Col. H. H. Godwin-Austen. 

 Twenty-four specimens, two of which are ovigerous females, rang- 

 ing in length from 24 to 42 mm. 



Manipur Hills, Manipur state. Col. H. H. Godwin-Austen. 

 Three specimens (none ovigerous ) from 24-5 to 28 mm. in length. 



These examples were found many years since and it must, 

 I think, be the case that the species is very strictly localised. 

 On a visit to Assam a year ago I had ample opportunities of 

 collecting freshwater Crustacea at Mangaldai in the Darrang Dis- 

 trict and on the neighbouring Assam-Bhutan frontier, locahties at 

 no great distance from Tezpur. Special efforts were made to 

 rediscover Xiphocaridina ; but the search proved quite unavailing, 

 although several interesting species of Caridina were obtained in 

 abundance in the tributaries of the Brahmaputra. 



For assistance in the identification of the specimens collected 

 by Col. Godwin-Austen I am under considerable obligation to Prof. 

 E. L. Bouvier, who was kind enough to forward me a transcript 

 of one of his papers on Atyid evolution that had not at that time 

 been received in our Calcutta libraries. He also furnished me with 

 several references which afforded valuable information and spared 

 me from his small series in the Paris museum a specimen of 

 X. curvirostris from New Zealand for comparison with the Assam 

 examples. 



Subsequently, Dr. C. Chilton, to whom I wish to convey my 

 sincere thanks, furnished me with a considerable number of speci- 

 mens, obtained in the R. Avon at Christchurch, New Zealand. 



I have thus been able to make a careful comparison oi: Indian 

 and New Zealand examples and no doubt whatever remains in my 

 mind of the complete identity of the two forms. Inasmuch, how- 

 ever, as this determination raises questions of geographical distri- 

 bution of no little importance a mere statement of fact would not 

 perhaps be acceptable and in searching for some standard of com- 

 parison between the two forms it has seemed best to adopt the 

 somewhat laborious method of measurements, as employed by de 

 Man (1908) in the discrimination of varieties oi Caridina nilotica. 

 The figures are shown in the tables on pp. 116— 117 and it will be 

 seen that, judged by this criterion, there is no room for doubt 

 regarding the identity of the forms from the two localities. In the 

 proportions of the antennular peduncle and antennal scale, in the 



