OXYCEPHALUS ClAURI. 61 



The species is at once distinguished from its congeuers by the 

 raised, almost prismatic dorsal sections of the pera^onal segments, by the 

 strongly protruding heel of the carpus of the second pair of perasopoda, 

 by the almost circular femur of the sixth pair, and by the tooth-like, 

 sharp-pointed projections on the under margins of the pleonal segments. 



The head (p. 22, fig. 7 and 8) is longer in the male than in the 

 female, especially the hind part of it. On the upper side the median 

 line forms a distinct keel, ending in the apex, which is feebly bent down- 

 wards. The under margins of the rostrum are serrated. In the male 

 the head is as long as the first six perseonal segments together, in the 

 female as long as the first four. 



The first pair of antennœ are like those in the preceding species, 

 but the last three joints of the flagellum are not longer than the breadth 

 of the first flagellar joint; the second is quite as long as the third, but 

 much thicker. 



The first pair of perœopoda (PI. I, fig. 21) have the carpus very 

 broad, with the lower front corner forming a broad angular heel at the base 

 of the metacarpus; the carpal process is like that in the preceding species, 

 but more strongly serrated and shorter than the hind margin of the meta- 

 carpus; the hind margin forms a thin, strongly serrated edge, the lower 

 corner of which is angular. The second pair (p. 33, fig. 54) are much 

 longer and stouter than the first pair; the carpus, without the process, 

 is only a fourth part longer than the metacarpus; the lower front 

 corner forms a broader heel than in the first pair; the carpal process is 

 bluntly serrated, and reaches almost to the apex of the dactylus. The 

 femur of the fifth pair is ovate, coarsely serrated on the front margin, 

 and considerably shorter than the three following joints together. The 

 sixth pair (PI. I, fig. 23) are much shorter than the fifth; the femur is 

 very broad, almost circular, serrated along the margins, and fully a third 

 part broader than that of the fifth pair; the carpus is a little more than 

 half as long as the tibia, with a row of longer and shorter spines along 

 the front margin, one long one and four short ones alternating; the dac- 

 tylus is serrated on the front margin. The seventh pair (PI. I, fig. 24) 

 reach fully to the apex of the carpus of the sixth pair; the femur is 

 about as long as that of the preceding pair, and a little more than half 

 as broad; it is longer than all the following joints together. 



The pleon in the male is as long as the last six peraeonal seg- 

 ments together; in the female it is as long as the last five. The lateral 



