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 oi Leander allied to L. styli/erus, 
Milne-Edwards, (iii) the Atyid genus Paratya (= Xiphocaridina) and (iv) the Penaeid 
g^nusAcetes. On these groups separate reports, including descriptions of a ilumber 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 Hymenicus 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, published onty 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 Australia, 
New Zealand and Norfolk I. 
1 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. A'. Zealand Inst., XL,IV, p. 128 (1912). 
