igi6.]' 



Fauna of the Chilka Lake : Terrestrial Isopoda. 



471 



lobe at the end. The third leg is similar to the second. The remaining legs increase 

 slightly in length up to the seventh (fig. 13, p. 468), and in all of them the merus and 

 carpus are slender, not expanded, and of the usual form, the propod in each is con- 

 siderably longer than the carpus. 



In the female, the legs have the same general shape, but the anterior pairs show 

 no broadening of the merus or carpus, and the propod of the first pair (fig. 14, p. 468) 

 is unarmed. They have the same structure as that seen in the posterior legs of the 

 male, except that in the anterior pairs in the female the propod is slightly shorter 

 than the carpus. 



The pleopoda on the whole resemble those of L. oceanica as described and figured 

 by Professor Sars (1898) and myself (1899). In the first pleopod of the male (fig. 15, 

 p. 469) the outer branch is very large, almost completely covering the inner branch and 

 the male appendage; its inner margin is not produced so much as in L. oceanica and 



Ligia exotica, Roux. 



Fig. 17. — Third pleopod of male, seen from posterior side. 

 Fig. 18. — Fourth pleopod of male. 



the outer angle is rather more rectangular. Its surface shows a branching structure, 

 presumably of blood vessels. The endopod is short and is produced at the inner distal 

 angle. The male appendage is slender, reaching slightly beyond the distal border of 

 the exopod and narrows throughout its length to a rather acute point. 



The second pleopod (fig. 16, p. 469) in the male has the exopod similar to that of the 

 first, but with its inner distal angle rather more rectangular. The endopod is modi- 

 fied into a 2-jointed male organ, the first joint much the shorter and lying trans- 

 versely, the second more than twice as long and extending considerably beyond the 

 exopod ; it is grooved throughout its length and ends with a slight irregular enlarge- 

 ment, portions of which are covered with thickly set, short setae, giving a roughened 

 surface like that of a file. 



The third, fourth and fifth pleopods (figs. 17, 18, 19) are similar to one another, 

 but the third and fourth are slightly larger than the fifth ; in all the exopod is much 

 larger than the endopod and, as in the first and second, has its margins fringed with 



