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



Second Gnathopods. — Side-plates almost semicircular. Branchial vesicles very small, 

 much shorter than the first joint. Marsupial plates very broad, rounded, much shorter 

 than the side-plates, very much broader than the first joint, with several long marginal 

 setae. The first joint reaching beyond the side-plate, about equal in length to the wrist 

 and hand, carrying setas on both margins ; the second joint with some apical setse 

 behind ; the third joint as long as the wrist, produced behind to a sharp apex, wdth a 

 group of setee above it and a row of three setse higher up on the hind margin ; the 

 wrist much shorter than the hand, triangular, distally cup-like, the hind margin furred, 

 the blunt apex carrying seven or eight spines ; the front margin of the hand more than 

 twice the length of the hind margin ; the hand widest at the commencement of the 

 very long and very oblique convex palm, along the commencement of which runs a row 

 of spines set closely together, the remainder of the palm being fringed with some setules 

 of various sizes ; the curved finger, besides the dorsal cilium near the base, and one or 

 two at the base of the nail, has four or five hairs along the otherwise smooth inner 

 margin. 



First Perseopods. — Side-plates broader above than below, both front and hind 

 margins nearly straight. Branchial vesicles small, pear-shaped, not so long as the first 

 joint of the limb. Marsupial plates verj^ broad, not very long. First joint reaching 

 below the side-plates ; many setae, some of them long ones, on the front margin, 

 chiefly on the lower half; the third joint curved, longer than the fourth, equal to the 

 fifth, a little decurrent in front ; these joints have a few small spines and spinules on 

 the margins ; the finger long, thin, pointed and curved, more than half the length of the 

 fifth joint. 



Second Permopods. — The side-plates of about equal depth and width, rounded 

 behind. The branchial vesicles rather larger than the preceding pair ; neither first nor 

 second joint of the limb reaching below the side-plate ; the third joint longer than 

 either the fourth or fifth ; the fifth longer than the fourth, each with four pairs of spines 

 on the hind margin ; the finger, like the rest of the limb, stouter than in the preceding 

 pair, more curved ; the inner margin smooth. 



Third Per«opo(is.— ^Side-plates small, lobed behind. Marsupial plates very small. 

 First joint not expanded, with a few spinules on the margins ; third joint longer than 

 fourth or fifth, with small spines at seven points of the front, and six of the slightly 

 decurrent hind margin ; fourth joint shorter than the fifth, with three groups of spines 

 on the front margin ; fifth joint with four groups ; finger much more than half the length 

 of the fifth joint. 



Fourth Perseopods. — Side-plates similar to the preceding pair, but smaller. First 

 joint of the limb ovoid, not much narrowed at either end, the sides almost entirely 

 smooth ; the rest of the limb scarcely diflering from the preceding ; the fourth joint has 

 four groups of spines on the front margin. 



