2i8 Memoirs of the Indian Museum. [Vol. V, 



Rliyiiclwplax^ and to Hymeniciis '\ the former of which genera, as Alcock has suggested, 

 is perhaps synonymous with the latter. It differs from both, however, in the simple 

 rostrum and, I believe, also in the slender chelae of the male.' In addition, it is 

 distinguished from Hymenicus, and perhaps also from Rlivuchopla.\\ by the well- 

 developed outer maxillipedes which completely occlude the buccal cavern. 



In addition to the points mentioned above, E. (Trigonoplax) cimex differs from 

 E. (T.) unguiformis in its narrower form, in the proportionately shorter antero-lateral 

 borders of the carapace, in the shorter legs and in the dactyli, which are slender 

 (not spatulate) and armed with a greater number of spines. 



The colouring of living specimens of E. [Trigonoplax) cimex is rather striking. 

 The carapace of an adult female was of a warm reddish-brown tone, tinged with 

 green posteriorly and with a Y-shaped mark of deep umber brown, incompletely circum- 

 scribed by cream, extending forwards and inwards on either side from the middle of 

 the lateral margin. The palm of the cheHpedes and the distal half of the propodus 

 of all the walking legs was very dark brown, nearly black. The remaining parts of 

 the legs were pale sienna brown. 



The carapace, when the animal is walking, is held almost vertically. 



The species is represented in our collection by eight specimens, of which, how- 

 ever, only two, which are ovigerous females, are of large size. All were obtained 

 during vSeptember 1914, in the outer channel of the lake, chiefly on the weedy and 

 muddy ground in the vicinity of Barhampur I. At the time they were taken the 

 water was quite fresh, but I have no doubt that they are also to be found in the same 

 locality at other times of the year when the water is as salt as that of the Bay of 

 Bengal. The species appeared to be very scarce and it was only with considerable 

 difficulty that specimens could be detected among the weed brought up b}- the nets. 



The type specimens are registered under nos. 8947-8/10. 



Family OCYPODIDAE. 



Subfamily OCYPODINAE. 



Genus OCYPODA, Fabricius. 



Two species of this genus, Ocypoda macrocera, Milne-Edwards, and 0. platyiarsis, 

 Milne- Edwards, are found living in the sand at the edge of the outer channel of the 

 Chilka Lake at all seasons of the year. They appear to be equally abundant in this 

 situation both when the water in the channel is fresh and when it is salt. 



0. cordimana , Desmarest, a species which has not been found in the lake-system, 

 is common on the seaward side of the sand-hills and may at times wander to the 

 shores of the outer channel. 



' Rhvnckoplax, Stimpson. Proc. Acicd. Nat. Sci. Philadelphia, X, p. 109 [55] (1858) and Smilhson. 

 Misc. Coll., XLIX, p. 147 (1907). 



- llymenirus, Dana, Atncr. Joiirn. Sci (2), XII, p. 290 (iSjr) and U. S. Explor Exped., Crust., 

 I> P- 387 (1852), redefined by Alcock, Journ. Asiat Soc. B ngdl, LXIX, p. ^87 (1900). 



* As has ahtady been pointed out, no lully athilt niales were obtained. 



