2go 



Memoirs of the Indian Museum. 



[Vol. V, 



Species. 



Group of A . nitescens. 

 A. nitescens, Leach 



A. naijaroensis, Coutiere 

 A. aretijormis , Coutiere 



A. grinialdi, Coutiere 

 A. granti, Coutiere 

 A. parvus, de Man 

 Group of A. dimorphiis. 

 A. dimorphus, Ortmann 

 A. minikoensis , Coutiere 

 A. haswelli, Coutiere 

 A. orientalis, Pearson 

 A. djiboutensis, Coutiere 

 A. sibogae, de Man 

 A. jedanensis, de Man 

 A. tennipes, de Man 



First pair of peraeopods. 

 Male. Female. 



Asymmetrical, both enlarged 



Unknown . . 



One enlarged, the other unknown 



Symmetrical, enlarged 

 Asymmetrical, both enlarged ? . . 

 Unknown.. 



Symmetrical, enlarged 

 Asymmetrical, both enlarged 

 Unknown. . 

 Unknown . . 



Asymmetrical, both enlarged 

 Asymmetrical, both enlarged 

 One enlarged, the other unknown 

 Unknown. . 



Asymmetrical, one only a little en- 

 larged. 



Symmetrical, not greatly enlarged. 



One not greatly enlarged, the other 

 unknown. 



vSymmetrical, enlarged. 



Asymmetrical, both enlarged P 



Symmetrical, not enlarged. 



Symmetrical, not enlarged. 

 Asymmetrical, one only enlarged. 

 One (? both) not enlarged. 

 Asymmetrical, one only enlarged. 

 Asymmetrical, one only enlarged. 

 Asymmetrical, both enlarged. 

 Symmetrical, not enlarged. 

 Unknown. 



The single species of Athanas found in the Chilka Lake belongs, apparently, to a 

 form hitherto unknown, but is closely allied to Ortmann's A . dimorphus . It was unfor- 



co 



Fig. 31. — Athanas polymor phus , sp. nov. 



a. First peraeopods of female. 



6. do. of male, form I. 



c. First peraeopods of male, form II. 



d. do. of male, form III 



tunately very scarce, and of the twenty-seven specimens obtained only nine are males. 

 These nine males, however, present a most notable diversity of form, a fact which 

 has led me to assign to the species the name Athanas polymorphus. 



As in A. dimorphus the first legs in the female are both slender (text-fig. 31^), 

 with the carpus longer than the chela and are wholly dissimilar in structure from the 

 large limbs of the male. But, apart from this feature, which evidently influenced 

 Ortmann in his choice of a specific name, the males in the new species can be sepa- 

 rated into three clearly defined groups according to the degree of development which 



