i 9 i6.] 



Fauna of the Chilka Lake ; Terrestrial Isopoda. 



463 



in 1852. Budde-L,und gave a Latin diagnosis of the species in 1885. In 1893, in his 

 account of the distribution of the genus Ligia, Dollfus briefly indicated the characters 

 by which L. exotica is distinguished from other species and gave a figure of the pos- 

 terior portion of the pleon and the uropoda (1893 A, p. 3). The only other descrip- 

 tion that I am acquainted with is that given by Miss Richardson in 1905 in her 

 monograph of the Isopoda of North America. She gives text-figures of the maxilli- 

 pedes and first peraeopoda and a reproduction of Roux' s original figure of the species. 

 She also gives an analytical key to the American species of the genus. 



Budde-Lund has called attention to the small process at the end of the propod 

 of the first gnathopod of the male, and Dollfus (1890, p. 7) has referred briefly to the 

 differences between the male and the female in the anterior peraeopoda, but these are 



Ligia exotica, Roux. 



Fig. 1. — ist antenna of male (highly magnified). 



Fig. 2. — 2nd antenna of male. 



Fig. 3. — Upper lip. 



Fig. 4. — Lower lip, seen from posterior side. 



the only references I can find to the sexual differences, and the pleopoda do not ap- 

 pear to have been described or figured in either sex. Miss Richardson gives an outline 

 drawing of the maxillipeds, but the other mouth-parts have not been figured nor 

 described in any detail. I have thought it desirable, therefore, to give figures and 

 descriptions of some of the more characteristic parts for comparison with Sars' 

 account of Ligia oceanica (1898, p. 156) and with that given by myself of Ligia novae- 

 zealandiae (1901, p. 107). 



Specific Diagnosis. Body oblong oval, greatest breadth about half the length of 

 body ; dorsal surface minutely granular, the granulations becoming smaller and less 

 evident on the segments of the pleon. Antennae about as long as the length of the 

 body. Uropoda when fully developed more than half the length of the body. First 



