278 



Memoirs of the Indian Museum. 



[Vol. V, 



U. infraspinis. 



Rostrum slightly shorter, with 5-7 teeth above ] 

 and 1 or 2 below. 



Basal segment of antennular peduncle narrower, 

 its outer margin nearly straight. 



Apex of antennal scale produced far beyond the 

 spine which terminates the outer edge. 



Second peraeopods with merus and ischium sub- 

 equal; palm a little shorter than ischium. 



Sixth abdominal somite less than twice as long as 



fifth. 

 Size larger, up to about 21 mm. 



U. indica. 



Rostrum slightly longer, with 8-10 teeth above l 



and 2 or 3 below. 

 Basal segment of antennular peduncle broader, 



its outer margin convex. 

 Apex of antennal scale produced not so far beyond 



the spine which terminates the outer edge. 

 Second peraeopods with merus decidedly shorter 



than ischium; palm little, if at all, more than 



half the length of ischium. 

 Sixth abdominal somite twice as long as fifth. 



Size smaller, not more than 16 mm. 



Some of these distinctions would perhaps break down on actual comparison of 

 specimens, while others, possibly of greater value, might be found. 



With the two remaining described species of Urocaris, U. longipes, Stimpson* 

 and U. psamathe, de Man 3 , the Indian form has little in common. 



I think it very probable that the specimen recorded by Pearson (loc. cit.) under 

 the name U. longicaudata , Stimpson, from the Ceylon Pearl Banks should be referred 

 to this species. In the Indian Museum are numerous examples of U. indica obtained 

 at the north end of the Gulf of Manaar, a locality not far distant from the Pearl 

 Banks, and these are indistinguishable from individuals found in the Chilka Lake. 

 The fact that an antennal spine was present in Pearson's example clearly indicates 

 that it was incorrectly referred to the West Indian species ; in the figures, however, no 

 ocellus is shown and the rostrum is less elevated than in any example of U. indica 

 that I have seen. 



Examined when alive, specimens of Urocaris indica are almost perfectly trans- 

 parent to the naked eye, but under a lens small speckles of white arranged in trans- 

 verse rows are seen on the abdomen, at the tip of the telson, on the uropods and on 

 the eyestalks. There are also minute maroon specks on the carapace and abdomen, 

 the amount of pigmentation present varying greatly in different individuals. The 

 eggs borne by the females are sage green in colour. 



This species is very common in the Chilka Lake, especially near the shores 

 among weeds. It is extremely abundant at the south end of the lake and at Barkul 

 and is equally common at localities near the inner end of the outer channel, where 

 the bottom is composed of muddy sand and weed is plentiful. The species is able to 

 tolerate extreme variations in salinity, having been found in water that was quite 

 fresh as well as in that which was as salt as the Bay of Bengal near the lake. 



Ovigerous females were found in February, March, July and September. In 

 the latter month, however, egg- bearing individuals were obtained only at the south 



1 Excluding the tooth situated on the carapace behind the rostrum. 



2 Stimpson, Proc. Acad. Nat. Sei. Philadelphia, XII, p. 39 (i860). 



3 De Man, Abhandl. Senckenb. naturf. Ges., Frankfurt, XXV, p. 816, pi. xxv, fig. 51 (1902), 



