REPORT ON THE AMPHIPODA. 727 



and backwards. First joint with the front margin very straight, carrying two setae or 

 cilia above and a few spines along its course, behind much expanded, serrate, narrowing 

 below and not overlapping the next joint; the third joint a little shorter than in the 

 preceding pair, the rest similar. Owing to the comparative narrowness of the first joints 

 in the third and fourth perasopods, and the breadth of the side-plates to which they are 

 attached, the third, fourth, and fifth perseopods stand well apart, instead of overlapping 

 above, as they so commonly do. 



Pleopods. — The peduncles powerful, with some setae, and four very slender coupling 

 spines in which the retroverted teeth are small, seemingly three or four in number ; the 

 cleft spines are three in number, placed high up on the long first joint of the inner 

 ramus ; the joints of the inner ramus number thirteen, those of the outer fifteen. 



Uropods. — The peduncles of the first pair longer than the rami, the rami unequal, 

 the lower with more spines and longer than the upper ; the peduncles of the second pair 

 equal to the shorter ramus in length ; peduncles of the third pair shorter than the rami, 

 which are short and broad, armed with a few cilia-like spines, pectinate on the edges like 

 those of the other two pairs, the lower longer ramus with a nail. 



Telson extending a little beyond the peduncles of the third uropods, not much longer 

 than its breadth at the base, cleft rather beyond the centre, not dehiscent, with one or 

 two cilia on each rather broad rounded apex, and one or two on the lateral margins 

 lower down than the top of the cleft. 



Length of the outstretched specimen, without the antennae, half an inch. 



Loccdity. — Station 156, Antarctic Ocean, February 26, 1874; lat. 62° 26' S., long. 

 95° 44' E.; depth, 1975 fathoms; bottom, Diatom ooze. One specimen. Trawled. 



Remarks. — It seems not inconsistent with the great depth from which this species is 

 reported to have been obtained that it should exhibit some striking peculiarities. The 

 specific name, coheres, intimates that it has gone shares with various groups in the 

 inheritance of its characters, as already exj)lained in the note upon the generic description. 

 The outer plates of the maxillipeds are very remarkable, and so also is the absence of the 

 accessory plate on the right mandible in combination with the character of a strongly 

 dentate cutting edge. As the observations are based upon a single specimen, however, 

 it is necessary to allow for the possibility of the plate being accidentally absent, though 

 there is no appearance in the specimen of any such loss. 



Family Stegocephalid.^, G. 0. Sars, 1882. 



Dana in 1852 makes the Stegocephalinae a subfamily of the family Gammaridae ; 

 Boeek in 1876 makes them a subfamily of the Leucothoidaj ; Sars in 1882 makes them 

 an independent family. Boeck gives the following definition : — 



