770 THE VOYAGE OF H.M.S. CHALLENGEE. 



of spines in front ; the fifth joint and finger much as in the preceding peraeopods, but the 

 joint rather shorter, th(? finger a little longer. 



Fourth Perwopods. — The side-plates similar to the preceding pair, but less broad. 

 The first joint broadly and evenly expanded, the front margin not very convex, fringed 

 with spinules, the hinder convex, almost smooth ; the rest of the limb like the third pair, 

 the third joint rather more decurrent, the fifth rather larger in both length and breadth. 



Fifth Perseopods. — The side-plates small, but as usual rather deeper behind than in front. 

 The first joint larger than in the preceding pair, the front margin more convex, the lower 

 margin behind comjjletely instead of partially overlapping the second joint; the remainder 

 of the limb not materially different, but the fifth joint and finger rather smaller; in one 

 member of the pair the fourth and fifth joints and finger were much smaller than in the 

 fellow limb, the fourth joint being completely overlapped by the apex of the third. 



Pleopods. — Coupling spines slender, curved, with the usual hooks ; a single cleft 

 spine on the inner ramus ; six joints to the inner, and eight joints to the outer, ramus of 

 the third pair. 



Uropods. — Peduncles of the first pair much longer than the rami, fringed with spines; 

 the rami equal, pectinate on the upper edges, the inner carrying two spines, the outer 

 one ; peduncles of the second pair about as long as the longer ramus ; both rami with 

 pectinate edges, the shorter with a marginal spine ; the peduncles of the third pair as 

 long as the proximal portion of the ramus, with an apical spine, and a second higher up ; 

 the proximal portion of the ramus much longer than the nail, carrying an apical spine, 

 and a smaller one on the surface. 



Telson very broad, longer than broad, apically converging to a rounded point ; near 

 each lateral margin there are three small spines, the middle one being at about the centre 

 of the margin. 



Length. — The specimen, in the position figured, measured, from the front of the head 

 to the back of the second pleon-segment, a little under one-fifth of an inch. 



Locality. — Station 313, off Cape Virgins, Patagonia, January 20, 1876; lat. 52° 20' 

 S., long. 67° 39' W.; depth, 55 fathoms; bottom, sand; bottom temperature, 47°'8. 

 One specimen, female. 



RemarJcs. — A total of five species of Metopa were obtained at this one station, the 

 rest of the voyage yielding but one other. 



The specific name refers to the compactness and comparative solidity of this species, 

 both in the parts of the animal and its whole figure. 



The figure lettered par. represents a parasite which infests this specimen, especially 

 about the telson and uropods. 



