I9I5-] 



Fauna of the Chilka Lake : Crustacea Decapoda. 



311 



recorded by Miss Rathbun l are specifically identical with that described by de Man. 

 The species, which should bear the name of L. robusta, Stimpson (de Man), is appar- 

 ently characterized by the absence of the special features that distinguish L. cari- 

 nata, L. serratorbita and L. gracilis and by the presence of three pairs of spinules on 

 the dorsal surface of the telson in addition to those at the apex. 



5. Leptochela aculeocaudata , Paulson 2 , is probably a close ally of L. robusta, from 

 which it is distinguished by the presence of only two pairs of spinules on the dorsal 

 surface of the telson in addition to those at the apex. 



Leptochela reversa, Bate 8 , is apparently a nomen nudum. 



The Indian form is provisionally identified with L. aculeocaudata, a determina- 

 tion which premises a considerable amount of error in Paulson's figures and that the 

 marked sexual differences in the carination of the carapace escaped his notice. 



Caullery (loc. cit. supra) in his account of the Decapoda collected by the f Caudan' 

 expedition has provided a valuable key to the five more well-established genera of 

 Pasiphaeidae. Leptochela is distinguished from other genera by the possesion of a 

 mandibular palp composed of a single segment and by the presence of laciniae on the 

 inner margin of the second maxilla. 



The branchial formula in the Indian species is apparently identical with that 

 found in Parapasiphaë, Smith : — 





VII. 



VIII. 



IX. 



X. 



XI. 



XII. 



XIII. 



XIV. 



Podobranchiae 



Arthrobranchiae 



Pleurobranchiae 



ep. 



ep. 



ep. 

 2 



1 

 1 



I 

 I 



I I 

 I I 



1 



•• 

 I 



Leptochela aculeocaudata, Paulson. 

 (Plate XIII, fig. 14.) 



1875. Leptochela aculeocaudata. Paulson, Crust. Red Sea, p. 100, pi. xvi, fig. 1. 



1906. Leptochela aculeocaudata, Nobili, Ann. Sei. nat. Paris, (9), IV, p. 28, text-figs. /\a-c. 



In dorsal view the rostrum is broad at the base, but narrows rapidly to a sharp 

 apex. It is very short; in the male it reaches only to the middle of the cornea, 

 while in the female it is rather longer and may reach to the end of the eyes ; it is 

 occasionally a little upturned at the apex. The rostrum bears a longitudinal dorsal 

 carina which extends backwards on the carapace. In the male this carina is not 

 sharp and disappears altogether before reaching the middle of the carapace. In the 

 female (pi. xiii, fig. 14) it is much more conspicuous and is continued to the middle 

 of the posterior quarter of the carapace as a thin compressed keel. In this sex there 



1 Rathbun, Bull. U. S. Fish Comm. for 1903, XXIII, p. 929 (1906). 



* Paulson, Crust. Red Sea, p. 100, pi. xvi, fig. 1 (1875) and Nobili, Ann. Sei. nat., Zool. (9), IV, 

 p. 28, text-figs. 4, a-c (1906). 



s Bate, Rep. 'Challenger' Macrura, p. 722 (1888). 



