296 Records of the Indian Museum. [Vol. XIII, 



genus no such distinction was to be found. It seems probable, 

 therefore, that in this genus, as in Paratya, the existence of sexual 

 modifications in the thoracic legs is a specific character. In Xipho- 

 caris, the most primitive of all the Atyidae, these sexual differ- 

 ences do not exist.' 



Bouvier,* in his account of the races of Atyaephyra desmaresti , 

 found that distinctive characters were afforded b}^ the structure of 

 the endopodite of the first pleopod of the male. In the genus 

 Paratya the appendage is similar in outline in all the forms and the 

 differences that exist in the spinulation appear to be of less im- 

 portance than those derived from other parts. 



All the species and subspecies examined agree in the posses- 

 sion of a supraorbital spine. The carpus of the first peraeopod 

 is deeply excavate in front, that of the second pair less markedly 

 so. Exopods are found on all the thoracic legs, but there are no 

 arthrobranchs above the bases of any of these limbs. The outer 

 uropod agrees with that of Xiphocaris in bearing only a single 

 movable spinule in place of the series found in most genera of the 

 family. The telson bears two, less commonly three pairs of dorsal 

 spines and is provided at the apex with eight or ten spinules 



A synopsis of the numbers of rostral teeth in the different 

 forms is given on p. 297. 



In the descriptions which follow I have referred only to the 

 characters that show racial or specific differences. 



Paratya comprcssa (de Haan) sensu stricto. 



1H49. 1 Epliy^'a conipressa, de Haan, in Siebold's Fauna jfapoiiicn. Crust., 



p. 186, pi. xlvi, fig. 7. 

 1880. Miet'sia compressa, Kingsley, Proc. Acad. Sci. Philndelpliia, 1879, 



p. 416. 

 1902. Xiphocaris coiupressa, Rathbun, Proc. U.S. Nat. Mus., XXVI, p. 49 



(? part only). 

 1905. Xiphocaris compressa, Bouvier, Bull. Sci. France Belgique, XXXIX, 



p. 62 (part only; not fig. i, p. 61). 

 1914. Xiphocaridina compressa, Balss., Abliandl. niath.-phys. Klasse K. 



Bayer. Akad. Wiss., Suppl. Bd. II, Abt. 10, p. 23 (part only). 



In this form the rostrum always reaches beyond the anten- 

 nular peduncle, extending almost to, or a little beyond the apex 

 of the antennal scale. On its upper border it is armed with 16 to 

 25 (usually 17 to 24) teeth, forming an uninterrupted series from 

 the base to the apex. The hindmost dorsal tooth is either situated 

 on the carapace or is placed immediately above the posterior limit 

 of the orbit ; in a few cases two posterior teeth are on the carapace. 

 The lower border bears in the middle of its length from i to 6 teeth, 

 most commonly i to 3. 



The lateral process of the antennular peduncle extends a little 

 beyond the end of the basal segment. 



i This statement is based on an examination of a few specimens from 

 Havana in Cuba, preserved in the Indian Museum 



2 Bouvier, Bull. Mus. d'Hist. uaf. Paris, igi^. p. 65. 



