82 THE VOYAGE OF H.M.S. CHALLENGER. 



The former are long clawed ambulatory limbs, which do not present any great 

 discrepancies of size in this species ; all four pairs are of approximately the same lengt h 

 and thickness; the structure of these limbs is so like that of other species that I need 

 not particularly describe them. 



The last three appendages of the thorax (figs. 9; 10) are swimming legs ; the last joint 

 but one of each appendage, and the joint in front of that again, arc flattened out and 

 fringed with hairs; the terminal joints of these limbs are narrow and claw-like, so that 

 they possibly subserve the double function of swimming and walking, especially since the 

 penultimate, and to a less extent the antepenultimate, joints are not very wide; not 

 nearly so wide as they are, for instance, in Eurycope (see PL IX. fig. 5) ; all the three 

 pairs of appendages are, in fact, closely similar to the last pair of thoracic append.; 

 in the genus Uyarachna (see p. 77). 



The uropoda (fig. 11) are of extraordinary length, quite as long if not longer than t In- 

 terminal spine of the abdomen ; the appendages are simple and composed of at least 

 five joints, more or less equal in length, and beset with a few scattered hairs. 



Station 158, Southern Ocean, March 7, 1874; lat. 50° 1' S., long. 123° 4' E. ; depth, 

 1800 fathoms; bottom temperature, 33° '5 F. ; Globigerina ooze. 



Acanthocope acutispina, F. E. Beddard (PI. VIII. figs. 1-5). 



Acanthocope acutispiwj, F. E. Beddard, Proe. Zool. Soc. Lond., 1885, pt. iv. p. 923. 



This species, which was dredged at Station 302 in 1450 fathoms, is very closely allied 

 to the last, but differs from it in a number of characters sufficient to necessitate its 

 separation as a distinct species. The single specimen is mounted on a slide in glycerine ; 

 it is of a uniform dark brown colour. 



The extreme length of the specimen is 5 mm. 



The head is rounded with an abruptly truncated frontal margin. 



The first segment of the thorax is much shorter and narrower than any of the suc- 

 ceeding segments; its lateral margins are rounded and not prolonged into spiny processes. 

 The three following segments gradually increase in width as well as Length up to the 

 fourth where the body is widest ; their lateral margins are prolonged into very long spiny 

 processes which are slightly curved, the direction of the curvature being anterior. The 

 three posterior segments of the thorax are together rather less in length than the first 

 four segments ; there is no great break between the anterior and posterior sections of the 

 body, the general outline being, therefore, as in Eurycope, oval : each of the three 

 posterior segments is, as usual, convex forwards and concave backwards, the antero- 

 posterior diameter of these segments is subequal. Like the anterior segments of the 

 thorax they are furnished with long lateral spines curved in a forward direction, though 

 the longitudinal axis of the spine gets to be placed more and more obliquely backwards 



