DESCRIPTION OF SPECIES 315 



of the joint, the other near its posterior end; Beddard noted a similar arrangement in 

 S. convexa. The two outer lobes of the maxilla, like those of S. convexa, are broad and 

 bear a number of serrated spines (seventeen on the outer and nine on the inner lobe) 

 instead of the more usual number of two. The basipodite of the maxilliped is separated 

 by a suture from the lamella ; the distal joint of the palp is very small. 



The second thoracic appendage of the male is figured and described by Audouin and 

 Milne-Edwards, and the types of sensory hairs present on the propodus are very similar 

 to those of the males of S. convexa and S. laevis ; as in these two species, I have observed 

 that there is here also a sexual difference in the form of the spines on the propodus, for 

 in the female the longer type of spine is replaced by one which has its distal end pro- 

 duced into two processes, one of which is slightly longer than the other. Between these 

 processes the central axis is continued as a prolongation extending to about the level of 

 the shorter process (cf. Fig. izb). A group of plumose setae is present on the carpus of 

 the second thoracic appendage of the male, as in S. convexa and 5. laevis ; long plumose 

 setae also fringe the inner margin of the ischium, merus, carpus and propodus of the 

 last thoracic appendage of the male. 



The protopodite of each of the first three pairs of pleopods is triangular in shape, and 

 the projecting angle is furnished with three plumose setae in the first of these appendages 

 and two in the second and third. The suture of the exopod of the fourth pleopod is 

 nearly transverse, and the endopod has a rounded distal extremity. The uropoda extend 

 to near the tip of the terminal segment ; the exopod is about two-thirds the length of the 

 endopodite, and has a broadly rounded distal extremity bearing a number of long 

 plumose setae. The distal extremity of the endopod is more pointed and is also fringed 

 with plumose setae. 



Distribution. Shores of South America; the original specimen was found near 

 Valparaiso. 



16. Serolis laevis, Richardson (Plate XIV, fig. 5). 



Serolis laevis, Richardson, 1911, pp. 399, 400, text-fig. 2; Nordenstam, 1933, p. 81. 



Through the kindness of Prof. Ch. Gravier I have been able to examine the type 

 specimen of this species from the Museum d'Histoire Naturelle, Paris, and since 

 Richardson's account consists merely of a brief comparison with the allied species 

 S. plana, Dana, S. convexa, Cunningham, and S . gaudichaudii, Aud. etEdw., I include a 

 description. This, however, is necessarily incomplete, as my observations were restricted 

 to such details as could be seen without the removal of any appendages. 



Description. The type specimen (Plate XIV, fig. 5) is an adult male measuring 1 6 mm. 

 in length and 11-5 mm. in greatest width. The body is ovate in shape, white in colour, 

 with a smooth surface, and a slight median dorsal keel. The head is broader than 

 long, broadest anteriorly, with a well-developed rostrum, and with antero-lateral angles 

 narrow. A slight transverse ridge extends across the head just behind the rostrum ; the 

 area between the eyes is convex. The eyes are sHghtly raised, reniform in shape, not 



