332 DISCOVERY REPORTS 



spine, lying midway between the posterior spine and the lateral margin of the segment. 

 Two small oblique ridges extend from either side of the base of the anterior spine and 

 terminate in small spines on a level with the lateral ones and midway between them 

 and the lateral margins of the segment. The uropoda are attached rather far back on the 

 terminal segment, a little behind the level of the posterior spine; both exopod and endo- 

 pod are well developed and the latter is the larger. 



Remarks. There is little to add to Beddard's account of this species, but a minor 

 point may be mentioned in connection with the third thoracic appendage of the adult 

 male. Beddard (18846, p. 59) describes the modified spines which are found on the 

 propodus of this limb, but does not mention that they only occur on the proximal half 

 of the joint, their place being taken distally by a double row of long branched setae 

 similar to those found on the inner margins of the merus and carpus. Similar setae, 

 though not so densely arranged, are found on the inner margins of the carpus, merus 

 and propodus of the last thoracic appendage of the adult male. 



Distribution. Beddard's specimens were collected at two stations, 42° 32' S, 

 56° 29' W, at a depth of 2040 fathoms, and 37° 17' S, 53° 52' W, in 600 fathoms. Those 

 in the present collection come from a locality a little farther to the south-west, between 

 46°-53° S and 6o°-63° W, and from depths of 242-434 m. 



24. Serolis minuta, Beddard. 



S. minuta, Beddard, 1884 i, p. 77, pi. vii, figs. 2-7; Whitelegge, 1901, p. 237; Chilton, 1917, p. 397. 

 S. minuta, Beddard var. eugeniae, Nordenstam, 1933, pp. 82-5, pi. i, fig. 3, text-figs. 11 h, 20. 



Diagnostic characters. The Challenger collection contained a single male mea- 

 suring 5 mm. in length, and 5 mm. in greatest breadth ; the two specimens mentioned 

 by Chilton (p. 397) are both females in the breeding condition, the larger of which 

 measures 8 mm. in length and 7 mm. in breadth. The male is therefore slightly broader 

 in proportion to its length than is the female, and the outline of the body is almost 

 circular. 



The head terminates in front in a short rostrum; the posterior margin is provided 

 with three blunt tubercles, the middle of which is the larger. Each of the following 

 thoracic somites has its posterior border produced into a median blunt spine. The third 

 to the seventh somites have well-developed coxal plates and those of the third to the 

 fifth somites are marked off by distinct sutures ; lateral tubercles are present on the 

 somites close to their junctions with the coxal plates. The tergum of the seventh somite 

 is partially fused with that of the first abdominal segment, the posterior suture of the 

 former being incomplete for a short space on either side of the middle line. 



The pleural plates of the second and third abdominal segments extend beyond the 

 coxal plates of the thoracic somites ; those of the third are sHghtly longer than those of 

 the second and extend to a point just beyond the base of the articulation of the 

 uropod. 



The terminal segment is "almost triangular in shape, and ends in a blunt prolonga- 

 tion ; the upper surface slopes gently downward on either side from the central keel ; the 



