112 



a pencil of setae. The last 3 pairs have the ventral border of the ischium and 

 merus closelv spinose, and also have some spines and spinelets on some of the 

 other joints : their dactyli are sharp and curved and have some very fine spinelets 

 along the ventral border. 



The abdominal appendages are all biramous, and have singularly long 

 protopodites, the postero-external edge of which is beset with bristle-like 

 spinules : all the rami, except the inner ramus of the 1st pair,' are long and 

 narrow: all the endopodites behind those of the 1st pair have a short internal 

 appendix, and in those of the 2nd pair in the male there are two of these. 



The exopodite of the tail-fan is imperfectly divided into two segments by 

 an incomplete transverse suture. 



The branchiae are 5 in number on either side, being pleurobranchiae attached 

 to somites X to XIV. In addition, 5 microscopic papillae are found the vestiges 

 of lost arthrobranchiae on somites TX-XTTT. Epipodites are present on the 

 1st and 2nd maxillipeds; but on the coxae of the external maxillipeds anc 

 thoracic legs there are small tubercles which may be the remains of lost epipo- 

 ditea. 



The efferent branchial channel is remarkably well defined by a incurved 

 process of the inflected postero-inferior angle of the carapace, the process 

 firmly catching the undermined posterior border of the hist thoracic sternum. 



Key to the (Indian) species of Psalidopus. 



L The thoracic and frfrrr ; -r 1 stem* -n -* ... ... ... P. 



Ti. The last three thoracic and all the abdominal (tens with a T^V*- 



"..ir Zlrili^ ji*r ... ... ... ... ... P. 



65. Psalidopus Huxley i, Wood-Mason. 



, ABB. Xac. Xti. His., April 1892, p. 273, pL zir. Sgt. 1 - I 



~. 



Rostrum nearly twice as long as the rest of the .carapace, with 4 rows of 

 spines, dorsal, ventral and 2 lateral ; the dorsal row is continued to the posterior 

 border of the carapace as a spiny carina, and die lateral rows are also continued 

 to tie posterior border of the carapace as ginnnna spinv ridges. Besides these 

 spiny carina?, and besides many other spines, the ridges that dpfinp the branchial 

 regions above and below, and the ridge that defines the branchial canal superiorly, 



Abdomen with a Tn*Kn spiny carina extending to the posterior border of 

 the 6th tergum, trifurcate on the 5th tergnm : with an irregular row of spines 

 on either side at the level of the junction of pleura and terga, and with other 

 spines between these rows. Tips of the pleura spinose. Dorsal surface of telson 



:-..;.- -::.-. 



