Memoirs of the Indian Museum Vol. V. Fauna of the Chilka Lake. No. 12. July 1924

775 the southern end and many are undoubtedly carried out to sea by the outflowing current, but at the extreme south end of the lake in Rambha Bay and to a certain extent in the deeper waters of the body of the lake the change in density of the water is not so great as in other parts and here the permanent inhabitants can survive until the subsidence of the flood waters again enables them to popul [...] The work of Thompson and A. Scott on the Copepoda of the Ceylon Pearl Banks resulted in the discovery of a number of forms that were previously unknown to us, but a comparison of the total number of species obtained by them with the profusion of forms described from the coasts of Great Britain and Norway by Brady, T. Scott, Norman and G. O. Sars sufficiently illustrates the extreme paucity of our [...] The period of the year during which it occurs in the collection is from February to April and in consequence it appears probable that the species is, like Isias clavipes, an inhabitant of the littoral zone and was bought in to the lake by the inflowing sea-water ; if this be so, further research should reveal its presence along the coasts of the Bay of Bengal. [...] The species of this genus appear to fall into two groups, characterised by the relative length of the terminal spine on the 5th leg of the female :- In group I these spines are all of approximately equal length and are, in comparison with the length of the leg itself, short. [...] In the majority of the members Of this group the habitat tends to be brackish or even fresh water though the last-named species appears to be an exception. ' Poppe and Mrazek (1894, p. 126) have called attention to an interesting modification that is present in the outer seta of the third last segment of the 1st antennae of the female and the unmodified antenna of the male in Pseudodiaptomus serr