Boone, Crustacea, Cruises of "Eagle" and "Ara," 1921-28 159 



anterior, being produced to an acute tooth which is directed slightly 

 posteriorly on the outer surface; there is a median depression; the 

 fifth segment is nearly one and one-half times as long as the fourth 

 and has its posterior margin similar across the median region and 

 including the small, rounded tooth on the upper lateral region; the 

 lateral part is different, the posterior lateral margin being scarcely 

 at all convex, while the anterior lateral region is very convex and bears 

 a small, acute, posteriorly directed tooth on the median part and a 

 large, triangulate, acute tooth at the apex which is directed pos- 

 teriorly; the sixth segment is narrower than and one and one-half 

 times as long as the fifth, transversely convex, with the lateral mar- 

 gin not produced; an acute, outward and posteriorly directed tooth 

 at the outer basal margin of the uropod, above which the margin of 

 the segment is excavate and produced into an acute, triangulate tooth 

 which projects above the telson near the outer basal margin; the 

 median posterior margin of the segment is relatively straight, with the 

 little, rounded tooth on either side. The telson is twice as long as the 

 fifth segment and narrow, tapering slightly to a triangular apex, the 

 dorsal surface flattened with a longitudinal depression and defined 

 from the narrow lateral part by a row of seven articulated spines on 

 each side set subequally; there are two similar articulated spines on 

 the terminal margin on each side of the apex. The uropoda are as 

 long as the telson and consist of a short, flat peduncle, which is pro- 

 duced at its outer angle into a broad, triangular process with a spine 

 at the apex, and a shorter, triangular inner lobe, the two being sepa- 

 rated by a V-like incision. The blades are both oval, the inner one 

 narrower and with a median, longitudinal ridge on the proximal part ; 

 the outer blade has a similar keel, the distal third of the blade partly 

 separated from the proximal by a suture, and there is an acute spine 

 on the outer lateral margin of the proximal section at this suture ; the 

 inner lateral margin is more convex than the outer. Both blades are 

 fringed distally with close-set, plumose setae. 



The eyes are small, cylindrical, the cornea terminal, shining black. 



The antennulae have the proximal article longer than the eyes, con- 

 cave beneath the eye, with the outer margin terminating in a slender 

 acute spine which has its base midway the joint and its apex reaching 

 to the base of the third joint ; there is a short, up-pointing spine on 

 the distal margin of the first article ; the second article is short, cylin- 

 drical, with an acute spine on its upper distal margin ; the third article 

 is very short and has an acute spine at its distal margin ; the flagellum 



