1922.] Fauna of the Chilka Lake : Observations in Rambha Bay. 693 



Annelida. 



Hirudinea. — Two species of Hirudinea were found in Rambha Bay in 1914, viz. 

 Glossosiphonia ceylonensis (Harding), and a new species of Piscicola. They have been 

 described by Mr. W. A. Harding, whose report on the leeches, as well as further 

 remarks by Dr. T. Kaburaki, have been already published in this volume. None 

 were collected in 1919-20, but no special search was made for them. I saw the 

 Piscicola in June, 1920, among algae at the end of the landing-stage at Barkuda 

 and obtained specimens in August from a pool on the island. The Glossosiphonia was 

 collected in 191 4 in flooded country at the head of the bay and is a true freshwater 

 species closely allied to G. heteroclita (Linn.) of Europe and N. America 



Oligochaeta. — The following species of oligochaete worms were taken on the 

 shores of Rambha Bay below water-level in 1914: — Enchytraeus barkudensis Stephen- 

 son and Pontodrilus bermudensis Beddard, f. ephippiger (Rosa). To these was added 

 in July, 1916, Monophylephorus parvus Ditlevsen, which was found in masses of rot- 

 ting weeds just afloat. This species has not been found since 1916, but conditions 

 for its propagation, apart from changes in salinity, were perhaps unsuitable in 1919- 

 20, owing to storms which washed away the dead weeds. The other species are 

 apparently still common, as was to be expected. 



Polychaeta. — Mr. R. Southern has recently published in this volume a full des- 

 cription of the species collected in 1914. The littoral Nereidae mentioned in his 

 paper as occurring in the main area do not seem to have been affected by the 

 physical changes that have taken place in the lake since that date, and no change has 

 been observed in the common species dredged off shore. 



Crustacea. 



Amphipoda. — The species collected in 1914 have been worked out by Prof. Char- 

 les Chilton, whose account has been published recently in this volume. Two am- 

 phibious species are common as " sandhoppers " on the shores of Rambha Bay, 

 namely Orchestia platensis Kröyer, and Talorchestia martensii (Weber), the former 

 being much the more abundant of the two. Nine true aquatic species occur. Of 

 these at least three are easily recognized and are well known to me. They are, 

 the new species of Niphargus, Quadrivisio bengalensis Stebbing, and Grandidierella 

 megnae (Giles). In saying that I am acquainted personally with the last I should 

 state that I have not attempted to distinguish between it and a closely allied new 

 species described in Prof. Chilton's paper. The two forms, however, occur com- 

 monly together. Niphargus, Quadrivisio and Grandidierella are all very abundant 

 among algae and stones on the shore of Barkuda Island and I noticed no diminution 

 either in their numbers or in those of the sandhoppers in 1919 er 1920. 



Isopoda. — The aquatic isopods collected in 1914 have not yet been identified, 

 but I may note some further facts about the terrestrial but strictly littoral species, 

 Ligia exotica Roux, which Prof. Chilton has already described in great detail in our 

 report on the fauna of the lake. In the rainy season of 1914 we observed this 

 species on the shore of Barkuda I. in great droves. They were also present in 



