163 



Antennae II in males are long, the 3rd and 4th segments of the peduncle 

 clavate, and the thin flagellum five-segmented. 



The outer lobes of the maxillipeds taper sharply in the distal part; 

 the fused inner lobes are roughly half the length of the outer, their apex 

 straightly truncated and bearing two setae. 



The structure of the appendages, particularly the last three pairs of 

 pereopods, is fairly constant. Pereopods III-IV are identical in length 

 and structure; the 4th and 5th segments are equal in length; the 6th 

 segment is slightly narrower and shorter; the claws are long and thin. The 

 139 2nd segment of pereopods V is slightly denticulate on the anterior^ and 

 posterior margins; its anterior distal angle is produced into a smooth acute 

 process, several times longer than the 3rd segment; the 4th segment is 

 roughly the same length as the 5th or slightly shorter than it, and together 

 they are longer than the 2nd segment; the 6th segment is weak and short, 

 usually 1/4-1/3/ the length of the 5th; the claws are short and curved. 

 Pereopods VI are noticeably shorter but stronger than pereopods V; the 

 2nd segment is smooth along both the anterior and posterior margins; 

 the 4th segment is longer than the 5th, which in turn is longer than the 

 6th or equal to it; the claw is long and slightly curved. Pereopods VII 

 are weak, their 6th segment longer than the 5th; the claw is long and 

 curved. Uropods I and II are uniformly finely denticulate on the posterior 

 margin; the posterior margin of uropods III is smooth. The telson has 

 parallel margins and is apically rounded. 



Notes: There are specimens in which the proportions of 

 pereopods V-VII differ from the typical: the 4th segment of pereopods V 

 is almost half the length of the 5th; the 6th segment of pereopods VI 

 and VII is notably shorter than the 5th; the claws of pereopods VI 

 and VII are shorter than in the typical form. Such differences from 

 the typical specimens have been observed in the specimens from the 

 tropical part of the Pacific Ocean and from the South and North Atlantic 

 (Barnard, 1932; Shoemaker, 1945a; Vinogradov, 1960a). The presence 

 of specimens exhibiting intermediate characteristics of these features 

 does not permit us to share the opinion voiced by Shoemaker about 



' Here and later, referring to the ornamentation of the anterior margin of the 2nd 

 segment of pereopods V, we permit some arbitrariness. This segment in the greater majority 

 of the Scina species is triquetrous in cross section; moreover its base forms the anterior 

 margin and its apex — the posterior margin of the segment.Both the anterior keels reach the 

 distal end of the segment where they unite to form a denticle in which the anterior distal 

 angle of the segment is produced ; the outerkeel is more chitinized than the inner one. In 

 mounted appendages only tHe outer keel is visible and in speaking about the ornamentation 

 of the anterior margin of the 2nd segment, we actually imply the ornamentation of only 

 the anterior outer keel. The inner keel is weakly armed in extreme cases similar to the 

 outer keel. In mounted specimens it is discernible with great difficulty. 



