OxYCEPHALUS PECTINATUS. 65 



long as it is broad at the apex, the three following joints together are 

 a little longer than the breadth of the first flagellar joint. The second 

 pair (p. 27, fig. 29) are longer and more robust than in Oxycephalus 

 piscator, or in 0. Clausi. 



The perceon is entirely smooth, and the epimerals are less deep 

 than in 0. piscator, scarcely equalling a fourth part of the height of the 

 peraeon. 



The first pair of perceopoda (PL II, fig. 5) are shorter than the 

 second; the front margin of the carpus runs in a line with that of the 

 metacarpus; the carpal process is about as long as the stem of the 

 joint, and is armed along its front margin with closely set, long, spine- 

 like teeth, which give a combe-like appearance to the whole; the apex of 

 the process forms a strong, sharp tooth. The metacarpus is stout, and 

 somewhat longer than the stem of the carpus; its hind margin does 

 not form an edge as in Oxycephalus piscator; it is as long, and armed 

 in the same way, as the front margin of the carpal process, but the 

 spine-like teeth are a little shorter. The dactylus is about a third part 

 as long as the metacarpus, and has a tooth at the middle of the hind 

 margin. The second pair (PL II, fig. 6) have the cheliform hand 

 comparatively much shorter than in Oxycephalus piscator or in 0. latiro-stris, 

 the carpus, without the process, being scarcely longer than the meta- 

 carpus; the front margin runs in a line with the front margin of the 

 metacarpus; the carpal process is longer than the rest of the joint; its 

 front side is armed as in the first pair, but the teeth composing the 

 pectination are much longer; the hind margin of the metacarpus, which 

 is considerably shorter than the carpal process, has exactly the same 

 pectination, and is bordered by four or five long bristles. The dactylus 

 is like that in the first pair. The fifth pair are the longest; the femur 

 is elongate, having the front margin straight and the hind convex; it 

 is more than twice as long as broad, and shorter than the three following 

 joints together. The femur of the sixth pair is a third part longer than 

 broad, and much shorter than the four following joints together, and has 

 the margins smooth; the front margins of the tibia and carpus are armed 

 as in Oxycephalus piscator; the front margin of the metacarpus has a 

 similar armature, but with a varying number of short spines between 

 the single long spines; the dactylus is strongly pectinated. The seventh 

 pair reach scarcely to the apex of the tibia of the sixth pair; the upper 

 hind portion of the femur is considerably dilated and forms an obtuse angle; 

 the metacarpus is as long as the carpus, and a trifle shorter than the tibia. 



Nova Acta Reg. Soc. Sc. Ups. Ser. III. 9 



