1386 THE VOYAGE OF H.M.S. CHALLENGER. 



joint of the peduncle broader and a little longer than the fourth, fifth joint longer than 

 the third ; flagellum linear, of more than thirteen elongate joints, of which the first is a 

 little bulbous at the base. 



Epistome domed, broader than deep, on one side projecting unsymmetrically. 



Upper Lip deeper than the epistome, unsymmetrically bilobed by an oblique apical 

 emargination. 



Mandibles and Maxillse nearly as in Hyperia sibaginis ; the palp of the first maxillee 

 longer in proportion to its breadth. 



Maxillipeds. — The outer plates rather large, with four little spinules along the inner 

 margin and two at the apex. 



First Gnatlwpods. — The upper boundary of the side-plates could not be clearly 

 distinguished in any part of the perason, though here and there faint indications of it 

 seemed to exist. The first joint as long as the following four together, most dilated at 

 the middle, the front margin being a little bowed out at that part, gland-cells visible in 

 the first joint as well in both gnathopods as in the peraeopods ; the second joint not 

 longer than broad ; the third joint longer than the second, forming a kind of pentagon 

 with three spines on the distal border which projects behind the wrist, the apex adjoining 

 the wrist being finely pectinate ; the wrist much broader but not longer than the hand, 

 with a spine at the apex of the convex front margin, two spines on the straight hind 

 margin, one at its produced apex, and four of less size within that apex ; the hand with 

 two spines on the convex front margin at the narrowed distal part, the hind margin 

 nearly straight, pectinate except near the base, the narrow apical margin finely pectinate ; 

 the finger slender, curved, more than half the length of the hand, its inner margin 

 microscopically pectinate. 



Second Gnathopods longer than the first ; the first joint a little widened distally instead 

 of at the centre, the wrist j^roduced to the middle of the hand and exceeding it in length, 

 the hand with a small and a large spine on the hind margin, the spines here as in the first 

 gnathopods being minutely plumose. The first and second gnathopods are, as usual in 

 this and some other genera, situated very close together, and are so arranged that until 

 they are separated it is not possible to obtain a lateral view of the lower joints of 

 both. 



First Pereeopods. — Branchial vesicles of ample size, a description which applies to all 

 the five pairs. The first joint narrow at the neck and slightly bent, then widened, 

 exceeding in width as well as in length the first joint of the gnathopods ; the second 

 joint longer than broad ; the third joint shorter than the fourth, with the hind margin 

 straight, carrying a small apical spine, the front margin very convex ; the fourth joint a 

 good deal shorter and wider than the fifth, the hind margin pectinate but not closely, 

 carrying a spine at the apex and one higher up, the front margin convex ; the distal 

 margin finely pectinate, projecting behind the fifth joint ; the fifth joint slender, curved, 



