314 DISCOVERY REPORTS 



The eyes of S. convexa are raised on prominences which might be described as conical, 

 and it is possible that Dana was referring to the shape of these rather than to that of the 

 eye itself — in which case the two species are identical. 



Locality. Patagonia, in a few fathoms.] 



15. Serolis gaudichaudii, Aud. et Edw. (Plate XIV, fig. 4). 



S.gaudichaudii, Audouin and Milne-Edwards, 1841 , p. 5, pis. i, ii ; Beddard, 1884 b, p. 38 ; Nordenstam, 

 1933. PP- 76-77. text-figs. 2e-g. 



Occurrence. St. WS 221 : 48° 23' S, 65° 10' W, 76-91 m.; i ? (b.). 



St. WS 742: 38° 22' S, 73° 41' W, 47-35 m.; i <? (young), 3 ??. 

 St. WS 809: 49° 28' 15" S, 66° 29' W, 107-104 m.; 3 immature. 

 St. WS 856: 46° 45' S, 64° 11' W, 104 m.; a number of immature specimens. 



Diagnostic characters. The largest specimen in the collection (Plate XIV, fig. 4) 

 measures 23 mm. in length and 17-5 mm. in breadth; it is approximately the same size 

 as an adult female of S. convexa, Cunningham, to which species it bears a very close 

 resemblance. The body, however, is more oval in shape, the decrease in width of the 

 thoracic somites being gradual: that is, the sixth and seventh somites are not con- 

 siderably narrower than the preceding ones as they are in S. convexa. The dorsal surface 

 is less convex than in S. convexa and a median keel is hardly discernible. 



The head, as in S. convexa, is slightly broader than long with its broadest part anterior ; 

 a median rostrum is present, behind which is a transverse ridge extending laterally to 

 the margins of the cephalosome. The eyes are raised on two postero-lateral rounded 

 prominences, between which the area of the head is sunken ; behind the eyes the median 

 area is slightly raised. The body colour is brown, darker in the mid-dorsal region, and 

 dotted all over with black spots. The eyes are small, but slightly larger in proportion to 

 the head than in S. convexa ; they are reniform in shape, prominent, and placed near 

 together. 



The first three free thoracic somites are sub-equal ; the fourth and fifth are narrow 

 and together equal to the third. The coxal plates of the first three free somites are 

 separated from them by distinct sutures ; those of the fifth free somite are broader than 

 the corresponding ones in S. convexa and extend backwards as far as the middle of the 

 terminal segment. The pleural plates of the second and third abdominal segments do 

 not extend backwards as far as the extremities of the coxal plates of the seventh thoracic 

 soinite ; those of the second are slightly longer than those of the third segment. 



The terminal segment is considerably broader and more rounded than that of 

 S. convexa, and is furnished with a central and two lateral dorsal carinae. The latter are 

 curved and follow the outline of the segment as far as the bases of the uropoda, where 

 they each terminate in a very small spiniform process ; these carinae are very much more 

 prominent in S. convexa. The middle part of the median carina is obsolete in both 

 species. 



Remarks. The head appendages are of the usual type. Most of the joints of the 

 flagellum of the antennule bear two sensory hairs, one situated near the distal extremity 



