I9 I 5-] Fauna of the Chilka Lake ; Crustacea Decapoda. 241 



Subfamily PLAGUSIINAE. 



Genus PLAGUSIA, Latreille. 



Plagusia depressa (Fabricius), subsp. tuberculata, Lamarck. 



1900. Plagusia depressa var. squamosa, Alcock, Journ. Asiat. Soc. Bengal, LXIX, p. 437. 



1906. Plagusia depressa vars. tuberculata and immaculata, Laurie, Rep. Pearl Oyster Fisheries, Ceylon, 



V,pp. 429, 430. 

 1906 Plagusia depressa tuberculata and P. immaculata, Rathbun, Bull. U.S. Fish Comm. for 1903, 

 III, pp. 841, 842. 



1907. Plagusia orientalis and (?) P. depressa, Stimpson, Smithson. Misc. Coll., XUX, p. 122. 

 1910. Plagusia tuberculata, Rathbun, Proc. U.S. Nat. Mus., XXXVIII, p. 590, and footnotes to 



references by Stimpson (op. cit.). 

 1910. Plagusia depressa tuberculata, Rathbun, Danske Vidensk. Selsk. Skrifter (7), Naturvid. og math., 

 V, p. 330. 



As Laurie and Miss Rathbun have remarked it is probably best, in view of the 

 uncertainty that exists regarding the identity of Herbst' s Cancer squamosus, to avoid 

 the use of that term as a varietal or sub-specific name. Examination of the speci- 

 mens in the Indian Museum leads me to believe that Alcock was right in refusing to 

 recognise more than one form of the species in Indian waters. The series shows 

 every possible intergradation between the vars. tuberculata and immaculata as defined 

 by Laurie. 



The only individual obtained in the Chilka Lake is extremely small, the carapace 

 being 7 mm. in length. The tubercles on the dorsal surface are much depressed, but 

 are heavily fringed with setae. 



The specimen was obtained in the outer channel in March 1914, at the time 

 when the water was salt. It was found clinging to a pole that served to mark the 

 deep water passage in the vicinity of Satpara. No specimens were observed when 

 the water was fresh and the species is doubtless to be regarded as a casual visitor to 

 the lake-system. 



The subspecies tuberculata, which is frequently found on floating timber far out 

 at sea, has a very wide Indo-pacific distribution, extending from the Red Sea and 

 Bast Africa to the western coasts of America from Lower California to Chili. 



Family GBOCARCINIDAB. 



Genus CARDIOSOMA, Latreille. 



Cardiosoma carnifex (Herbst). 



1900. Cardiosoma carnifex, Alcock, Journ. Asiat. Soc. Bengal, L,XIX, p. 445. 



1907. Cardiosoma carnifex, Rathbun, Mem. Mus. Comp. Zool., Harvard, XXXV, p. 26. 



The two specimens found in the Chilka Lake agree closely with other examples 

 in the Indian Museum and differ from C. hirtipes, Dana 1 , in the characters noted by 

 Alcock and Miss Rathbun. There seems, however, to be some variation in the degree 



1 Miss Rathbun [Bull. U.S. Fish Comm. for 1903, pt. 3, p. 838 (1906)] identifies this species with 

 the earlier Thelphusa rotunda of Quoy and Gaimard. 



