620 THE VOYAGE OF H.M.S. CHALLENGEK. 



and the apex in front ; the fourth joint simihirly armed, stouter than the fifth, in length 

 subequal to it ; the fifth with numerous short as well as long setiform spines on the 

 hinder margin ; two very short ones at the junction with the slightly curved finger. 



Second Perseopods. — Side-plates excavate far down, the lower margin curving up to 

 the excavation so as to form a rounded point. Branchial vesicles broad except at the 

 neck. Joints of the limb similar to those of the preceding pair. 



Third Perseopods. — Side-plates rather wider than deep, front margin very convex, hind 

 margin nearly straight. First joint a round oval, broader above than below, the rounded 

 lower margin behind reaching as far down as the second joint, front margin with 

 numerous spines fringing it entirely, hind margin serrate ; third joint much longer than 

 broad, somewhat decurrent behind, with spines at the back, spines and setae in front, 

 and a25ical groups of spines ; fourth joint scarcely so long as third, similarly armed ; fifth 

 joint much narrower but longer than fourth, with eight sets of spines on the front 

 margins, some spinules on the back border ; finger about half the length of the fifth joint, 

 slightly curved. 



Fourth Perwopods. — First joint a long oval, narrower below than above, spines on 

 the front margin few and small on the upper part, numerous and longer below, hind 

 margin serrate ; third joint as in the preceding pair, but somewhat longer ; fourth joint 

 longer than third, with nine groups of spines on the front border ; fifth joint scarcely 

 shorter than the fourth, with ten groups of spines on the front border ; small spines on 

 the hind margins of third, fourth and fifth joints ; finger not nearly half as long as the 

 fifth joint. 



Fifth Perxopods. — Branchial vesicles a broad oval, with the hiind margin drawn out 

 into somewhat pointed processes. First joint broadly oblong with rounded corners, the 

 front margin as in the preceding pair, the hind margin serrate, rather deeply at the 

 lower part ; the third joint shorter and narrower than in the two preceding pairs, with 

 four groups of spines in front, and four behind ; fourth joint longer than third, with 

 eight groups of spines in front, three behind; fifth joint longer than fourth, with nine 

 groups of spines in front, five behind, these latter being all very small, except the apical ; 

 finger not half the length of the fifth joint. 



Uropods. — Peduncles of the first pair longer than the rami, rami subequal, stiliform, 

 spines numerous on the peduncles and also on the rami. Peduncles of the second pair a 

 little longer than the rami ; the rami stout, the outer somewhat longer than the 

 inner ; marginal spines numerous. Peduncles of the third pair shorter than the rami, 

 the rami broadly lanceolate, almost equal, extending much further back than the second 

 pair ; spines on both edges ; plumose set^ also' on one. 



Telson long, extending far beyond the peduncles of the third uropods, cleft for 

 more than four-fifths of its length, narix)wing distally, a series of five spines along each 

 side ; in each apical cleft two spines, of which the outer is the larger. 



