226 ZOOLOGY OF the; FAR EAST. 



the undetermined material lying in the Indian Museum and to present the results con- 

 currently with those derived from Dr. Annandale's collection. The literature of the 

 subject being so widely scattered I have found that a great economy in time is effected 

 by this procedure, and the conclusions reached are, I believe, of much greater value 

 than if either collection had been examined separately. The groups treated in this 

 manner are (i) the Hymenosomatidae, (ii) the species of Leander allied to L. styliferus, 

 Milne-Edwards, (iii) the Atyid genus Paratya (= Xiphocaridina) and (iv) the Penaeid 

 genns A cetes. On these groups separate reports, including descriptions of a number of 

 the new species, have been already published in Vol. XIII of the Records of the Indian 

 Museum. 



Dr. Annandale has generously presented a complete set of the specimens he ob- 

 tained, together with the types of the new species and subspecies to the collection of 

 the Zoological Survey of India (Indian Museum) . 



Family HYMENOSOMATIDAE. 



In the course of his tour Dr. Annandale obtained two species of this interesting 

 family, both apparently new. Descriptions of these forms have been published in 

 Vol. XIII of the Records of the Indian Museum in a paper devoted mainly to the 

 elucidation of the Indian representatives of the family. In this paper I have 

 attempted a revision of the genera and have pointed out that the Indian species 

 referred by Alcock to Hymeniciis should more properly be grouped under Stimpson's 

 Rhynchoplax. Dana's Hymenicus is in my opinion synonymous with White's Hali- 

 carcinus. 



It is unfortunate that both Dr. Tesch and I should have been occupied with this 

 family at the same time without knowledge of each other's work. Tesch' s report on 

 certain crabs obtained by the ' Siboga ' Expedition, pubHshed only five months after • 

 my own paper, also contains a revision of the genera of this family. In the applica- 

 tion of Rhynchoplax we are, for the most part, in agreement ' ; but Tesch retains 

 Hymenicus as a distinct genus and in less important details our work shows a number 

 of discrepancies. 



Rhynchoplax introversus, Kemp. 



1917. Rhynchoplax introversus, Kemp, Rec. Ind. Mus., XIII. p. 262, figs, iia-c. 



This species, which is readily distinguished from any other by the peculiar form 

 of the lateral border of the carapace, is based on two specimens obtained in the 

 Tai-Hu lake in China, living in water that is quite fresh at all seasons of the year. 

 The only other Hymenosomatid known from fresh water beyond the reach of all tidal 

 influence is Halicarcinus lacustris (Chilton) ^ which has been recorded from Austraha, 

 New Zealand and Norfolk I. 



I Dr. Tesch places Hess's H. Kreffti and Haswell's H. rostrata under Rhynchoplax. According to my views both these 

 species are to be referred to Halicarcinus or, if it really be distinct from the latter, to Hymenicus. This is certainly true 

 of Haswell's species of which I have seen specimens. 



2 Chilton, Trans. N. Zealand Inst., XLIV, p. 128 (1912). 



