132 CARL BOVALLIUS, THE OXYCEPHALIDS. 



ural segment, and are nearly as long as the third pair. The 

 outer ramus of the first two pairs is nearly as long as the 

 inner; the outer ramus of the third pair is not half as long 

 as the inner. 



The telson is about as long as the last pair of uropoda, and 

 is as long as the urus. 



COLOUR. Light red all over the body. 

 LENGTH. 45 60 mm. 



HAB. The tropical region of the Atlantic, at Lat. 17 30' N., Long. 

 37 5' W. 



Xiphocephalus Lilljeborgi differs from the other species in 

 the form of the first pair of peraeopoda and their epimerals, in the form and 

 length of the seventh peraeonal segment, in the length of the first pair 

 of uropoda, and in the relation between the rami of all the three pairs. 



The perceon. The first segment is about two-thirds as long as the 

 second; the seventh is scarcely a fourth part shorter than the sixth. 



The epimeral of the first pair of peraeopoda is deeper than long, 

 obtusely triangular, with the apex directed straight downwards. That 

 of the seventh pair has the hind corner a little projecting downwards, 

 with the apex obtuse. 



The perceopoda. The carpal process of the first pair (PI. VII, 

 fig. 23) is triangular, armed with two low teeth on the hind margin, and 

 provided with two or three broad teeth on the front margin, which is a 

 little longer than the hind margin of the metacarpus, but does not attain 

 the middle of the dactylus; the hind margin of the metacarpus is pro- 

 duced at the lower corner into a rounded and serrated process; the 

 dactylus is strongly curved, and is quite as long as the metacarpus. 

 The second pair (PL VII, fig. 24) are much longer than the first; 

 the carpal process is very slender and sharp-pointed, reaching far beyond 

 the apex of the metacarpus, and beyond the middle of the dactylus. 

 The third and fourth pairs are similar in shape and equal in length; 

 the tibia is about as long as the femur. The fifth and sixth pairs 

 are sinilar in shape, but unequal in length, the sixth pair being distinctly 

 longer than the fifth; the metacarpus is scarcely longer than the carpus. 

 The single joint of the seventh pair is almost truncated at the apex. 



The pleon is not carinated, and is longer than the whole perseon. 

 The under margin of the segments is convex; the hind corner is feebly 

 produced and sharp-pointed. 



