1128 THE VOYAGE OF H.M.S. CHALLENGER. 



hind margin, those near the apex forming a broad row of very long thin spines ; the slightly- 

 curved front margin is slightly armed at three points ; the fifth joint is longer than the 

 third or fourth, narrowing a little distally, with seven groups of slender spines behind, 

 with spinules at two points high up on the slightly curved front, and a group of setae 

 or setiform spines at the apex ; the finger is about half the length of the fifth joint, and 

 has an opening in the apex. 



Second Peraeopods. — These, with their side-plates, are in close agreement with the 

 preceding, but a little longer ; the third joint has six or seven groups of spines, the 

 fourth has five, and the fifth has eight, on the front margin. 



Third Perseopods. — The side-plates nearly as deep as the preceding pair, and full 

 as broad even below, considerably broader above by the addition of the small hind lobe. 

 The branchial vesicles as broad as the first joint. The marsupial plates are similar in 

 general character to the preceding pairs, but considerably shorter, and more continuously 

 tapering. The first joint irregularly shaped, about as broad as long, the front and hind 

 margins both very convex, the front with seven short, stout spines, followed by some on 

 the lower part that are more slender ; the second joint short, longer behind than in front, 

 with some small spines in front at the apex ; the third joint rather longer than the 

 fourth, with spines at three or four points behind and two in front ; the fourth joint 

 with spines at two points on each margin, those at the apices being long ; the fifth joint 

 longer than either the third or fourth, with six gi'oups of spines along the hind margin, 

 comprising strong and slender spines in each group, the apex of the joint on the inner 

 side forming two small laminar projections, on the outer side set with numerous slender 

 setse much longer than the finger ; the finger curved, acute, about half the length of 

 the fifth joint. 



Fourth Perseopods. — The side-plates shallow, with several setse on the front edge of 

 the front lobe; the 'hind lobe less deep but broader tban the front, with a spine in a 

 notch at the lower hind corner. The branchial vesicles large and inflated. The limb 

 longer than the preceding pair. 



Fifth Perieopods. — The side-plates not bilobed, rather deeper behind than in front. 

 The limb longer than the preceding pair ; the first joint pear-shaped. 



Pleopods. — The peduncles (at least of the first pair), instead of the more usual 

 pair of coupling spines on each peduncle, have a row numbering about a dozen ; they are 

 short and small, with one pair of retroverted hooks at the apex ; the cleft spines form a 

 row of nine ; the joints of the outer ramus number twenty- two, of the inner twenty- three ; 

 the second and third pairs are very like the first, but perhaps with fewer coupling spines, 

 seven or eight cleft spines in a series, and a joint less in each of the rami. 



TJropods. — The peduncles of the first pair longer than the rami, with strong spines on 

 the inner or upper margins, and slight ones on the lower or outer margin ; the outer 

 ramus a little shorter than the inner, both with stout spines along the inner margin and 



