264 Records of the Indian Museum. [Vol, XIII, 



with 6 to 8 small rather widely separated teeth that occupy the 

 greater part of the length of the posterior border. 



In the abdomen of the male (text-fig. ric) the penultimate 

 piece is of the usual form, but is very strongly narrowed distally. 

 The terminal segment is exceptionally' long, its length being nearly 

 twice its basal breadth. 



The species is described from two males, in one of which — 

 much the larger of the two — the carapace is 5*4 mm. in length. 



In most respects R. introversus is intermediate between R. 

 exiguus and R. inachoides , but differs from both in the form of the 

 postero-lateral border of the carapace. It resembles R. inachoides 

 in the character of the dactyli of the walking legs, but the legs 

 themselves are shorter, the rostral lobes shorter and blunter and 

 the carapace broader. 



The specimens were found by Dr. Annandale in the Tai Hu 

 Lake in the Kiangsu Province of China. The larger individual was 

 found off the mouth of the Tong Dong Ding Creek and the smaller 

 at the mouth of the Moo Too Creek. Both were dredged in water 

 about 2 metres in depth. Dr. Annandale noted that the speci- 

 mens were pale buff in colour with brown markings on the cara- 

 pace somewhat like a fleur-de-lys. 



The species is remarkable in that it was obtained in pure 

 fresh water far beyond the reach of tidal influence. A consider- 

 able number of Hymenosomatidae have been found in localities 

 where the salinity is low and some appear to be able to exist in 

 water that is quite fresh during a portion of the year. But the 

 only species hitherto recorded from permanently fresh water is 

 Halicarcinus lacustris (Chilton),' which has even been found 3,000 ft. 

 above sea-level. 



The type specimen, the larger of the two individuals, bears 

 the number 9730/10 Zool. Surv. Ind. 



Rhynchoplax inachoides (Alcock). 



lyod. Hymenicus inachoides Alcock, 'Joitrn. Asiat, Soc. Bengal. I. XIX, 

 p. 388, and (1902) Illnsf. Zool. ' hivcstigator.' pi. Ixix, fig", i. 



I have little to add to Alcock's description of this species. 

 The post-ocular denticle is clearly visible in dorsal view ; the fingers 

 of the chela of the male meet throughout their length and are 

 armed with a regular series of teeth ; the abdomen in the same sex 

 is narrow and similar to that of R. demeloi. 



The only known specimen is the male described by Alcock 

 and found by Wood- Mason, along with R. wood-tnasoni , at Port 

 Canning near Calcutta On a recent tour in this locality I tried 

 to obtain further specimens but was unable to find either 

 species. 



' ['"or references see p. 247. 



