1312 THE VOYAGE OF H.M.S. CHALLENGER. 



joints of the limb, except perhaps the finger, longer ; the third and the fifth joints are 

 subequal in length ; the outstretched limb rather more than seven-tenths of an inch long. 

 Third Peraeopods. — Side-plates broad and shallow, especially in front. Branchial 

 vesicles and marsupial plates like the preceding pair. First, third, and fourth joints 

 longer but less broad than in the second peraeopods, the structure in general similar ; 

 the fifth joint shorter than in the preceding pair, shorter than the fourth joint, straight, 

 little narrowed distally, apically produced in a narrow lobe behind the finger ; the 

 finger extremely narrow except at the base, very small and strongly bent upwards, with- 

 out teeth on the inner margin ; the outstretched limb three-quarters of an inch long. 



Fourth Per&opods. — Side-plates not narrowly produced forwards like the preceding 

 pairs, the front lobe the smaller, the hinder produced downwards at the back in a small 

 point. Branchial vesicles large, the oval rather abruptly narrowed some distance 

 above the apex. The outstretched limb more than an inch long; the long first 

 joint has a folding in of the hind margin near the base, fringed with spines ; the 

 front margin and the longitudinal ridge of the upper surface near the hind margin 

 carry small spines ; the third joint is intermediate in length between the first and fourth, 

 the fifth joint is rather longer than the first, the armature of all these both on margins 

 and ridges being very inconspicuous ; the retractile finger is very small, strongly bent, 

 narrowing rapidly from the base to the bend, the inner margin fringed with minute 

 teeth, of which those near the base are inclined backward. 



Fifth Peraeopods. — Side-plates not very broad. The outstretched limb over two- 

 fifths of an inch; the first joint longer than the following three together, with fifteen 

 spines along the front margin, and nine or ten on the hind margin, the three ridges 

 smooth ; the third joint longer than the fourth, shorter than the fifth, which is not so 

 long as the first joint ; the finger as in the fourth peraeopods. 



The relative proportions of the peraeopods may be represented by the numbers 80, 

 86, 90, 122, 50. 



Pleopods. — The two slender coupling spines have each on either margin three or four 

 retroverted teeth below those of the apex; the cleft spine nearly as in Lanceola pacifica; 

 the rami are about equal in length, but in the pair examined there are on the somewhat 

 stouter inner ramus only fifteen joints, and eighteen on the outer ; the long first joint 

 of the inner ramus has eight feathered setae on its inner margin below the cleft spine ; 

 and on the outer margin of the first joint of the outer ramus the setae are also numerous. 

 Uropods very similar in character to those of Lanceola pacifica, but the rami of the 

 second pair do not exceed in breadth those of the first pair, or scarcely so, the 

 peduncles of the third pair are less unequal to those of the second pair, and the inner 

 ramus of the third pair is not noticeably shorter than the inner ramus in either of the 

 other pairs. 



Telson triangular, about once and a half as long as the breadth at the base, not 



