1552 THE VOYAGE OF H.M.S. CHALLENGER. 



pectinate with closer, finer, and more decurrent teeth along the front margin, the apex 

 also pectinate and slightly produced behind ; the finger nearly straight, pectinate on the 

 inner margin, rather more than a quarter of the length of the fifth joint. 



Fifth Perasopods. — First joint pear-shaped, longer than the other joints together ; 

 second joint not longer than broad, third straight, more than twice as long as the 

 second ; fourth shorter than the third, with convex front margin ; fifth shorter than the 

 fourth, with hind margin convex, and the front straight ; the exceedingly minute finger 

 forms a blunt triangle in front, with a slender curved process behind it, extending from 

 near its base beyond the apex. 



Pleopods. — Peduncles broad, not very long ; coupling spines broad-headed, with 

 some lateral teeth below the apical ; the cleft spine with the longer arm very slightly 

 dilated, placed at the broad top of the first joint of the inner ramus, and followed by 

 six or seven plumose setae along the inner margin of the same joint ; the first joint of 

 the outer ramus has eight or nine plumose setae on the outer margin ; joints of the 

 inner ramus eleven or twelve, of the outer twelve or thirteen. 



Uropods. — Peduncles of the first pair shorter than the rami, the distal margin 

 pectinate on the under surface ; the rami elongate, three-sided, reaching beyond the 

 other pairs, the outer rather shorter than the inner, pectinate along two edges, the inner 

 margin near the base smooth, convex, the joint then narrowing rather abruptly, the 

 inner ramus also pectinate on two edges ; peduncles of the second pair longer than the 

 outer, shorter than the inner, ramus ; the outer ramus almost smooth on the outer 

 margin, pectinate on the inner, much shorter and narrower than the inner ramus, which 

 is pectinate on both margins, but smooth on the upper part of the inner ; peduncles 

 of the third pair not longer than the distal breadth ; the outer ramus shorter and much 

 narrower than the inner, pectinate on both margins of the narrow lower part ; the inner 

 ramus broad till near the apex, then almost abruptly narrowed, pectinate on the lower 

 part of each margin. 



Telson reaching about to the apex of the inner ramus of the third uropods, rather 

 longer than broad, not quite so long as the preceding composite segment, the end 

 broadly rounded. 



Length, with pleon flexed, under three-tenths of an inch. 



Locality. — October 1875, South Pacific, surface. One specimen, female, with 

 numerous e^gs. 



Remark. — The specific name refers to the great size of the first joint in the third 

 peraeopods, which seems to distinguish this species from all others as yet described in this 

 genus. 



