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



or fifth, with groups of long setae on the lower part of the hind margin and apex in front ; 

 the fourth joint equal to the fifth in length, but much broader, with setse near the middle 

 of the hind margin and low down on the front margin, and behind, near the juncture 

 with the fifth joint, four broad spines, the lower pair as long as the fifth joint, which 

 is straight, armed in front below with six strong spines ; the finger is nearly as long 

 as the preceding joint, minutely pectinate on the inner margin, which runs out into a 

 little tooth before reaching the nail. 



Second Perwopods. — Side-plates little longer, though considerably broader than 

 those of the preceding segment, the hinder margin concave. The branchial vesicle very 

 long, not broad. The first joint reaching below the side-plate, but it must not be 

 supposed that the figures in the Plate, drawn from flattened dissections, represent the 

 relations of limb and side-plate in this broad-backed animal when whole. This limb has 

 the joints somewhat longer than those that correspond in the first perseopods, to which 

 it is in general similar. 



Third Perseopods. — Side-plates with the hind lobe rather broader and longer than 

 the front. Branchial vesicles long- oval as in the preceding pairs, but shorter. The 

 marsupial plates in the specimen figured were short and narrow, with a few long setse 

 round the apex and part of the front margin. The first joint not so broad as the side- 

 plate, slightly longer than broad, the breadth almost uniform, the hinder surface hairy, 

 the front margin fringed with setse, especially below, with one s^^ine at the a^^ex ; the 

 second joint overlapped by the first behind ; the third joint short but broad, widening 

 distally, with one apical spine behind, in front four groups ; the fourth joint short, 

 broad, squared, a little narrowed distally, with two groups of spines behind, and three 

 in front, the apical groups almost encircling the joint ; the fifth joint narrow, straight, 

 shorter than the fourth, with two groups of spines in front and one behind ; the 

 finger narrow, acute, as long as the preceding joint. 



Fourth Perseopods. — The side-plates and branchial vesicles small. The first joint, 

 like most of the limb, larger than in the preceding pair, the hind margin concave, ciliated, 

 the front a little sinuous but chiefly convex, armed with numerous groups of long setae as 

 well as with spines, behind broadly overlapping the second joint, which in front carries 

 two groups of spines ; the third joint armed as in the preceding limbs, but much larger, 

 greatly expanded below, the front margin straight, the hinder much curved ; the fourth 

 joint not much longer than its width at the base, with two groups of sjJines on the 

 straight front margin, and one at the apex of the hinder one ; the fifth and sixth joints 

 as in the preceding pair. 



Fifth Pergeopods. — The first joint greatly dilated, especially below, so that the three 

 following joints turned backwards do not reach the serrate hinder border ; the front 

 border is convex, with some small set93 and spines, at the apex a large and a small 

 spine ; the interior of this broad joint is largely occupied with packets of gland-cells 



