6g4 Memoirs of the Indian Museum. {Vol,. V 



August and for the greater part of September, 1919. About the end of that month 

 they began to disappear and by the end of October not a single specimen could be 

 found. In December also the species appeared to be entirely absent, but in April a 

 few young individuals were seen on rocks and stones at the edge of the lake 1 . At the 

 beginning of June the species was again becoming fairly common and fairly large, 

 but no full-grown individuals occurred, while at the end of that month full-grown 

 individuals were abundant. In August the individuals were as large and the droves 

 as populous as in the same month in 1919. These phenomena are evidently seasonal 

 and it is improbable that they are affected by changes in the salinity of the water, for L. 

 exotica, though it takes to water readily and is a good swimmer, habitually lives on 

 dry land. Our former notes on its habits were made in the rainy season of 1914. 

 Cumacea. — Only two species of Cumacea (Iphinoe sanguinea and Paradiastylis 

 culicoides Kemp) were taken in the lake in 1914, and of these only the latter was 

 found in Rambha Bay. In April, 1920, Major Sewell and I dredged specimens, pro- 

 bably belonging to the Iphinoe, just outside the bay. 



Stomatopoda.- — Dr. Kemp found only one species of Stomatopod in Rambha 

 Bay, namely S quitta scorpio Latreille. The very great majority of the specimens 

 belonged to this var. immaculata. In 1914, many adult individuals of this variety 

 were observed under stones on the shore of Barkuda I. and in similar situations, 

 but none were found in 1919 or 1920. In the rainy season of the former year, how- 

 ever, and as late as December, young specimens, an inch or more in length, were com- 

 monly dredged from the bottom of the bay. None were obtained in April, 1920, but 

 a few larvae were observed on the surface with Lucifer hanseni. 



Mysidacea. — Dr. Tattersall has recorded three species of this group as occurring 

 in Rambha Bay. They are Rhopalopthalmus egregius Hansen, Macropsis orientalis 

 and Potamomysis assimilis Tattersall. These species, which are easily recognized, 

 were abundant in 1914, and equally so in 1919 and 1920. The first has been taken in 

 the open sea and belongs to a marine genus, but the two latter are brackish-water 

 forms occasionally found in fresh water at. a considerable distance from the sea, but 

 not as a rule in isolated bodies of water. 



Decapoda. — No less than 23 sepcies of Crustacea Decapoda were taken in Ram- 

 bha Bay in 1914, and, thanks to Dr. Kemp's enthusiastic study, we know more about 

 the distribution in the lake of this group than about that of any of the other larger 

 groups of animals represented in its fauna. Of the 23 species 10 belong to the Rep- 

 tantia, 6 are crabs in the ordinary sense of the word, 3 hermit crabs and one a burrow- 

 ing shrimp-like form belonging to the tribe Thalassinidea. 



Of the six crabs, two (Ebalia malefactrix and Philyra alcocki Kemp) are small and 

 rather scarce species dredged occasionally in 1914 from the bottom of the lake. My 

 investigations in 1919 and 1920 were not sufficiently comprehensive to demonstrate 

 their absence in these years bej^ond doubt, but I am convinced that they were at any 

 rate scarcer than before. A single specimen of the Philyra was dredged off Nal- 

 bano, which lies some little distance to the north-east of Rambha Bay near the 

 opening into the outer channel of the lake, in December, 1920. Two other species 



L I have observed this also in February, April, May and June 1922. 



