1922.] Fauna of the Chilka Lake : Observations in Rambha Bay. 695 



{Varuna litterata (Fabr.) and Pachygrapsus pvopinquus de Man) are littoral, in damp 

 weather practically amphibious, species. In 1914, they were common on the shore 

 of Barkuda I., which I made my headquarters in 1919 and 1920 on several occa- 

 sions for several weeks at a time. I found neither at any season in these years. The 

 two remaining crabs, Scylla serrata (Forsk.) and Neptunus pelagicus (Linn.), are both 

 free-swimming species, but Scylla serrata at any rate is often found in holes at the 

 bottom. In the Chilka Lake both are caught for food. A fisherman I employed at 

 Barkuda occasionally brought me the Scylla both in the rainy season of 1919 and in 

 the hot weather of 1920. I saw fresh claws of N. pelagicus dropped by a fishing- 

 eagle on Barkuda in December, 1919. 



The three hermit-crabs (Clibanarius padavensis de Man, C. longitarsis (de Haan) 

 and C. olivaceus Henderson) are all conspicuous species, partly amphibious in habits, 

 and were found in 1914 on the landing-stage at Barkuda and among the rocks at the 

 base of Ganta Sila across the bay. In the main area of the Chilka Lake the only 

 Gastropod shell large enough for the body of adults is that of a species of Cuma 

 closely allied to C. carinifera (Lamarck). Subfossil shells of this mollusc, found 

 living in Rambha Bay in 1914, are still abundant all round Barkuda, but the hermit- 

 crabs entirely disappeared as the lake became fresh. 



Upogebia heterocheir Kemp, the only other representative of the Reptantia 

 found in Rambha Bay, burrows in the soft mud in the open parts of the lake. It 

 was if anything more abundant in April, 1920, than it was at any season in 1914. 



The thirteen species of Decapoda Natantia collected in Rambha Bay in 1914 be- 

 long to five families, which it will be convenient to deal with separately to some extent. 

 These families are the Palaemonidae, the Alphaeidae, the Atyidae, the Penaeidae 

 and the Sergestidae. I shall discuss these not in taxonomic order but rather in 

 reference to their habits. 



The Palaemonidae and Atyidae may be considered together first, as they are in 

 the main freshwater Crustacea whose presence in the lake provides perhaps the chief 

 lacustrine or fluviatile element in its fauna. The Palaemonidae were represented in 

 the bay in 1914 by three species of the freshwater genus Palaemon and by one of Uroca- 

 ris, which is mainly marine. The names of the species are Palaemon lamarrei Milne- 

 Edwards, P. rudis Heller, P. scabriculus Heller and Urocaris indica 1 Kemp. The 

 three former were seasonal visitors to the lake, which they probably entered from 

 bodies of fresh water for the purpose of breeding. P. rudis did so regularly and in 

 large numbers, while the other two species were rarely met with. P. rudis, indeed, 

 was one of the common prawns of the lake in a commercial sense in the rainy season. 

 I have no reason to think that any change took place in this respect in the monsoon 

 of 1919, in which the prawn-fishery was said to be particularly good. The specimens 

 of prawns I saw in Rambha Bay at this season seemed to me to be P. rudis. The 

 habits of Urocaris indica, which has also been taken in the sea, are different. It is a 



1 Dr. Kemp has recently revised the subfamily to which this species belongs and considers that 

 it should be known as Periclimenes (Periclimenes) indicus. See Rec. Ind. Mus. XXIV, p. 144 (1922). 



