REPORT ON THE AMPHIPODA. 1589 



the distal margin is more finely pectinate than the upper part of the joint ; the fifth 

 joint decurrently pectinate with teeth of various sizes along the front margin and with 

 slender close-set teeth round the apex ; the finger straight, acute, half the length of the 

 preceding joint. 



Fifth Perseopods. — First joint shorter than in the third perseopods but not less 

 broad, longer than the following joints together, the hind margin irregularly convex ; 

 the second joint as broad as the third, not longer than broad ; the third a little longer 

 than the fourth ; the fourth rather longer than the fifth, slender, tapering ; the finger 

 minute, straight. 



Pleopods. — The coupling spines very small, the arms of the cleft spine short, and the 

 subapical dilatation small ; the joints of the rami about twelve in number. 



Uropods. — Peduncles of the first pair rather longer than the rami, three-sided ; 

 the rami long, equal, three-sided, pectinate on two edges, reaching nearly to the apex of 

 the telson ; peduncles of the second pair much shorter than those of the first, shorter 

 than the rami ; the rami broadly lanceolate, the outer a little shorter than the inner, 

 which is as long as those of the first pair, the edges pectinate below ; the peduncles of 

 the third pair little longer than broad, shorter than the rami ; the outer ramus a little 

 shorter and much narrower than the inner, the edges pectinate, more loosely on the 

 outer than on the inner margin. 



Telson triangular, much longer than broad, if reckoned from the base of the third 

 uropods, the apex acute ; the telson forms a shield under which the rami of the third 

 uropods are neatly packed away, the rami in this position covering its whole under 

 surface except the narrowed apex and a small triangular space at the base. 



Length, a little over half an inch. 



Locality. — South Pacific, between Api and Cape York ; surface. One specimen, male. 



Remarks. — Claus' specimen from Zanzibar was a female not fully adult, 8 mm. in 

 length, and differing from the Challenger specimen in not having the hind margin of the 

 hand of the first gnathopods produced along the finger, and in having the fifth peraeopods 

 relatively much smaller, but in other respects the two specimens are so closely alike that 

 it seems undesirable to separate them specifically. It is possible that this species may be 

 the same as Guerin's Oxycephalies Oceanians, or that species may be the same as 

 Claus' Oxycephalies similis, but it is not possible, I think, to determine such questions. 



Oxycephalies porcellus (PI. CCTV., A). Specimen B. 



Head as long as the perseon, rostrum acute, nearly as long as the ocular region of 

 the head, its margins sparsely and shallowly serrate; the coalesced fifth and sixth 

 segments of the pleon not so long as the telson, but broader. 



Upper Antennae. — First joint of peduncle not very broad, second short ; first joint 



