56 



CARL BOVALLIUS, THE OXYCEPHALIDS. 



a 2. The lateral parts of the pleonal segments are 

 armed with a strongly projecting tooth on the 

 under margin. The lower front corner of the 

 carpus of the second pair of perseopoda is 

 strongly protruding, forming a broad heel in 

 front of the base of the metacarpus. 



2. 0. Clausi. 



B. The hind margin of the metacarpus of the first and se- 

 cond pairs of perseopoda is smooth. 3. 



<C. The hind margin of the metacarpus of the first and se- 

 cond pairs of perseopoda is pectinated. 



C 1. The seventh pair of perseopoda are scarcely more 

 than half as long as the sixth pair. The telson 

 is more than half as long as the last ural segment, 

 and is longer than the last pair of uropoda. 



C 2. The seventh pair of perasopoda are nearly as long 

 as the sixth pair. The telson is half as long as 

 the last ural segment, and is shorter than the last 

 pair of uropoda. 



0. tuberculatus. 



4. 0. pectinatus. 



5. 0. latirostris. 



1. Oxycephalus piscator, H. MILNE EDWARDS, 1830. 



PL I, fig. 816; and p. 28, fig. 33, 35, and 36; p. 29, fig. 37, 41, and 

 42; p. 36, fig. 66; p. 37, % 68 and 69; p. 39, fig. 75. 



Diagn. The body is compressed, and not tuberculate. The segments 

 of the perawn are smooth, not angulated or tuberculated. 



The head is shorter than the peraeon, with a short rostrum 

 which is abruptly narrowed near to the apex in the male, 

 but evenly tapering in the female. The hind part of the head 

 is about twice as long as the rostrum, and is somewhat de- 

 pressed in the male, but inflated arid globular in the female. 



The front margin of the carpal process of the first and second 

 pairs of perCBOpoda is longer than the hind margin of the 

 metacarpus, which is serrated, and bordered with strong- 

 bristles; the lower front corner of the carpus is a little pro- 

 truding in the first pair but not at all in the second. The fifth 

 pair are much longer than the sixth. The femur of the sixth 

 pair is irregularly pear-shaped, only a little broader than that 

 of the fifth, and somewhat longer than that of the seventh 

 pair which is shorter than all the following joints together. 



