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half the length of the rest of the carapace, is broad depressed and slightly 

 declivous in its basal half, and upcurved and strongly compressed in its distal 

 half : it is armed on either margin, near the middle, with a large tooth, and 

 beyond this, ventrally, with a single curved spine : its margins are continued 

 backwards, nearly as far as the broad deep cervical groove, as a pair of strong 

 outstanding carina?, each of which is cut into three teeth — the first tooth being 

 much the largest : between these two carina? is a low median ridge. 



The post-antennal spine is trenchant, wing-like, and of great size, its base 

 reaching nearly to the hepatic groove, its tip reaching beyond the base of the 

 antennal scale : behind and below it is a hepatic spine, while between it and the 

 great postrostral crest are 4 spines — one postorbital, and three in an oblique 

 series higher up. 



Behind the cervical groove the carapace is longitudinally traversed by 7 

 ridges — a median, which is really double, and 3 on either side — not including a 

 marginal ridge : the median ridge is coarsely granular or dentate and ends 

 anteriorly in a pair of spines, the 3 lateral ridges end anteriorly each in a little 

 spine. The general surface of tbe carapace is finely tomentose. 



The abdominal terga from the 2nd to the 5th are smoothly sculptured on 

 one plan : their broad smooth lateral and posterior borders are raised, and they 

 are traversed fore and aft by a low broad median ridge, and the area on either 

 side of the ridge is symmetrically eroded. The 6th tergum is armed with 3 

 spines — one in either lateral area and one in the middle of the posterior border — 

 not including the spine in which each of its pleura ends. 



The square telson lias a spine at either posterior angle and a pair of median 

 spines near its anterior end : the outer angles of the caudal swimmerets are 

 acutely produced, and the greater part of the edge of the transverse suture of 

 the outer swimmeret is serrated. 



The abdominal pleura from the 2nd to the 5th are recurved and acute. The 

 1st abdominal sternum has a strong (epimeral) tooth or spine outside the arti- 

 culation of either of its appendages : in the male, the sterna from the 2nd to 

 the 5th have a small median spine. 



The eyes are very large, and the proximal end of the basal joint of the 

 antennular peduncle forms, dorsally, a smooth plate, upon which the eye partly 

 rests. The antennal scale is almost hemispherical, with the convexity inwards, 

 its length is about a fifth that of the carapace. 



The external maxillipeds reach a little beyond the antennal peduncle : their 

 ventral border is setose and the inner border of their ischium is furnished with 

 an elegant set of teeth. 



The 1st pair of legs in the adult male are almost as long as the entire body, 

 more than half their length being contributed by the hand : the ischium is 



