290 Records of the Indian Museum. [Vol. VIII, 



east India. Palaemon hendersoni is known from Darjiling and 

 the border of the Southern Shan States. Caridina weberi, which 

 appears to have a very wide distribution in India, Burma and 

 Malaysia, is represented in the Brahmaputra valley by a race which 

 will in all probability prove to have a definite geographical signi- 

 ficance. The collections in the Indian Museum indicate that 

 Caridina hodgarti extends along the base of the Himalayas from 

 the Tista and Mahananda rivers eastwards to the Abor country. 



Of the new forms which are described the most interesting 

 appear to be Caridina excavata and C. hodgarti, which, in the 

 reduced number of their epipods differ from all species of the 

 genus in which such details have received attention. In a previ- 

 ous paper ^ I have remarked on the presence of Xiphocaridina 

 curvirostris , a primitive form hitherto known only from New Zea- 

 land, in the Upper Brahmaputra valley, and the existence of these 

 two aberrant species of Caridina suggests that the Atyid fauna of 

 N.-E. India is likely to prove of exceptional interest. 



It need hardly be pointed out that the description of the 

 crabs noticed in this paper would have been almost impossible had 

 it not been for Alcock's comprehensive memoir on the Indian 

 Potamonidae. 



On the species of Geotelphusa obtained in the Abor country 

 many examples of a Temnocephalid were found. These have been 

 identified by Mr. F. H. Gravely as Temnocephala semperi, Weber (see 

 p. 229 of this volume). Moreover, certain eggs found in the gill- 

 chambers of Caridina, on comparison with those found in a simi- 

 lar situation in other parts of India, afford evidence of the exist- 

 ence of Caridinicola'^ in the Brahmaputra valley. 



For assistance in making collections both of Decapoda and of 

 other groups I am under a great debt of gratitude to the Officers 

 of the 32nd Sikh Pioneers. To them, and in particular to Capt. 

 the Hon. M, de Courcy, I have to express my thanks. 



The type specimens of the new species are preserved in the 

 Indian Museum. 



Family POTAMONIDAE. 

 Sub-family POTAMONINAE. 



Genus Potamon, Savigny. 



Sub-genus Potamiscus, Alcock. 



The sub-genus Potamiscus was instituted by Alcock to receive 

 those species of Potamon in which the flagellum of the exopod of 

 the outer maxiUipedes is absent or vestigial. It is probable that 

 several species of Potamonidae already described really belong to 

 this sub-genus, but the character has been overlooked by the 

 majority of authors, and the confusion is increased by the fact 



1 Rec. Ind. Mus., VIT, p. iit. (1912). 



i Caridinicola : a genus belonging to the Temuocephaloid Tamily Scutarie!- 

 lidaeisee Annanriale, Rec Ind. Mus., VTT, p. 24'^, T912). 



