68 



The first two pairs of thoracic legs resemble those of Pasiphsea and other 

 allied genera : they are longer and very much stouter than any of the others, 

 the 2nd pair being longer than the 1st, and they end in elongate chelae with long 

 slender hooked fingers : in the 2nd pair the fingers, in addition to the close-set 

 comb of teeth found in other Pasiphseidx, are armed with long acicular teeth at 

 regular intervals. 



The 3rd and 4th pair of legs are long and filamentous, the endopodites 

 longer than the exopodites. The 5th pair are stouter than the 3rd and 4th and 

 end in a stoutish flexed dactylus : the exopodite in this pair is longer than the 

 endopodite. 



The abdominal appendages are biramous and are remarkable for the slender- 

 ness of both rami, and for the enormous length of the exopodites. The short 

 endopodites have the usual internal appendix, while is filiform. The exopodite 

 of the caudal swimmerets (which are of the usual form) is incompletely fissured 

 transversely. 



The eggs are few and large. 



The branchial formula is as follows : — 



Total l+3ep. 6 5 = 12 + 3 ep. 



Key to the species of Psathyrocaris. 



I. The dorsal edge of the rostrum is flush with the gastric carina : the 

 2nd pair of thoracic legs are as long as the whole body without 

 the telson, their merus is smooth aud articulates end to end with 

 the moderately long carpus : — 



1. Eyestalks moderately depressed : — 



i. Integument smooth : appendages sparsely setose ... P.fragilis. 



ii. Integument furfuraceous : appendages thickly setose P. plurnosa. 



2. Eyestalks sublaminar ... ... ... ••• P-platyophthalmus. 



II. The rostrnm is humped dorsally : the 2nd pair of legs are half the 



entire length of the body, their merus has its posterior border 

 serrated and articulates with the middle of the posterior border 

 of the extremely short carpus ... ... . ... ••• P. infirma. 



