34° 



DISCOVERY REPORTS 



28. Serolis nototropis, n.sp. (Figs, id, 16, 17). 



Occurrence. St. WS 796: 47° 49' 37" S, 63° 42' 30" W, 106 m.; 3 ?? (b.). 

 St. WS 797: 47° 45' i8" S, 64° 10' 30" W, 117 m.; I 9 (b.). 

 St. WS813: 51° 35' I5"S, 67° 16' 15" W, 106 m.; i ? (b.), 2 immature (J^. 

 St. WS815: 51° 51' 45" S, 65° 44' W, 132-162 m.; I (J. 

 St. WS 816: 52° 09' 45" S, 64° 56' W, 150 m.: I ?. 

 St. WS837: 52° 49' i5"S, 66°28'W, 98 m.; 13. 



Description. The body (Fig. 16) is longer than broad, almost oval in shape, but 

 narrowing posteriorly; the dorsal surface is arched, with a pronounced median keel 

 which is better developed in the male than 

 the female. The surface of the body is 

 slightly pitted and covered with rows of 

 conical papillar projections (Fig. ly a). 

 The only adult male measures 1 1 mm. in 

 length and 8 mm. in greatest breadth, 

 the largest female 12 mm. in length and 

 9 mm. in greatest breadth, so that in this 

 species the ratio of length to breadth is 

 approximately the same for the two sexes. 



The head is broader than long, shield- 

 shaped, with the greatest width anteriorly. 

 A short rostrum is present, on either side 

 of which the anterior margin is excavated 

 for the reception of the antennules, and 

 immediately behind this margin a trans- 

 verse ridge extends across the width of 

 the head. The eyes, which are situated 

 on raised areas, are placed rather close 

 together near the posterior border of the head ; the area of the latter between the eyes 

 and the anterior transverse ridge is raised. The eyes are small, oval in shape, and contain 

 black pigment. 



As in all the Serolidae the second thoracic somite is fused with the head ; the lateral 

 portion is smooth, but in the middle line, behind the head, the surface is raised into a 

 small dorsal spiniform process. The third and fourth thoracic somites are sub-equal, 

 the fifth and sixth are together equal to the third, whilst the seventh is equal to the sixth 

 but is fused with the first abdominal segment for a short distance on either side of the 

 middle line. Small median spiniform processes, decreasing in size from before back- 

 wards, are present near the posterior borders of the third, fourth and fifth somites. The 

 coxal plates of the third to the seventh somites are well developed and those of the third, 

 fourth and fifth are separated from their respective somites by sutures ; in both sexes 

 those of the seventh somite are more produced than those of the other somites and 

 extend backwards to about the level of the base of the uropod. 



Fig. 16. Serolis nototropis, n.sp.,?: x 10. 



