PASIPHAEIA MAGNA. 177 



whole body ; it is laterally compressed, and rises into a ridge along the whole 

 length of the dorsum ; the ridge is rounded, except on the anterior part 

 of the gastric area, where it assumes the form of a sharp keel, and is continu- 

 ous witli the acute-tipped, blade-like tooth which simulates a true rostrum ; 

 this tooth reaches forward nearly to the anterior extremity of the eyes ; its 

 lower margin is convex, with its hinder part resting closely upon, and ap- 

 parently anchylosed with, the frontal region of the carapace ; the frontal 

 margin is convex, rounded, and furnished below with long cilia ; it is 

 free from, and not continuous with, the carinal tooth. The infra-orbital 

 and antennal angles are rounded ; a sharp spine lies just back of the 

 antero-lateral margin, on a level with the middle of the basal segment of 

 the antenna ; below this spine, the antero-lateral margin turns backward, 

 and after running horizontally for a short distance, turns downward at 

 a (rounded) right angle, and joins the infero-lateral margin. There is 

 a well defined, blunt ridge on each side of the carapace, running from the 

 hepatic area backward over the branchial region and becoming obsolete 

 just before attaining the posterior border of the carapace. 



All the abdominal segments are carinated in the median dorsal line, 

 though on the first segment the carina is obsolescent. The sixth segment 

 is one third longer than the fifth segment ; it is marked on either side by 

 a curved longitudinal ridge. Tiie dorsal face of the telson is channeled ; 

 its posterior margin in the sole specimen procured is injured, so that its 

 contour and armature cannot be discerned. 



The eyes are of moderate size, black, and borne on stout peduncles. 



The flattened antennular spine (stylocerite) is equal in length to the 

 basal segment. The outer antennular flagellum is about equal to, the inner 

 a little shorter than, the length of the carapace. 



The second antenna is equal in length to the whole body. There is an 

 acute spine on the peduncle, below the articulation of the scale. The scale 

 is long oval in form, armed with a small tooth at the distal end, and over- 

 reaches the antennular peduncle by one half its length. 



The third maxillipeds extend forward as far as the end of the antennal 

 scale. 



The first pair of legs, when extended forward, surpass the third maxil- 

 lipeds by the length of the dactylus. The merus is armed with four or five 

 spines on its inferior edge. The basal part of the propodal segment is some- 

 what shorter than the dactylus. 



