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



of tlie palp ; on the inner and apical margin twelve spines may be counted, those lowest 

 down being small, the four at the apex the largest, tlie outermost conspicuously 

 exceeding all the rest ; the first joint of the palp short, with one long pectinate spine 

 on the inner, and one spine or seta on the outer, apex ; the second joint larger than the 

 outer plates, with several spines on the inner and apical margins ; third joint longer 

 than first ; finger long, with a short nail, dorsum cilium near the base of the finger. 



First Gnathopods. — Side-plates narrow at the base, very greatly dilated below, 

 projecting over the base of the lower antennas. First joint of the limb projecting little . 

 beyond the side-plate, very broad, dilating downwards, with setae along the front margin ; 

 the second joint with several tufts of setse or rather long pectinate spines on the hind 

 margin ; third joint a long triangle with the point downwards, with no free anterior 

 margin ; the wrist triangular, cup-shaped, behind carried out into a lobe flanked by the 

 apical margin of the third joint and the hind margin of the hand, but with a narrow 

 interval on each side ; the hind margin of the third joint and of the lobe of the wrist 

 just mentioned are armed with long geniculate pectinate spines, and also with rows of 

 shorter, but strong and strongly pectinate spines, increasing in length distally ; the 

 powerful hand is longer than broad, widest at the palm, with convex front and concave 

 hind margin, the latter set with six strong spines, increasing in length towards the palm, 

 and with pectinate spines or setse, such as occur also on various parts of the surface of 

 the hand ; the hind margin runs out into a long sharp tooth, the point of which contains 

 at the back a small spine with accessory thread, just showing its tip beyond the point ; 

 the inward sloping palm is convex beyond the triangular apex, and is set with spinules, 

 one stronger and blunter than the rest being close to the hinge of the finger ; the finger 

 itself overlaps the tip of the palm with its sharp nail, and seems to be without other 

 armature than the minute dorsal cilium, and a sharp but short projection of its inner 

 margin one-third of the distance between the hinge and the tip ; on either side of this 

 process is a cilia-like spine. The hand may be described as chelate. 



Second Gnathopods. — Side-plates oblong in general character, less wide than the 

 preceding pair. Branchial vesicles large, narrowed below. The limb weak, first joint 

 slender, not projecting beyond the side-plate ; second joint much longer than third, 

 equal in length to the wrist, furred on the lower part of the hinder margin ; third joint 

 skort, equal in length to the hand, furred on the hinder margin ; the wrist strongly 

 furred almost all over, carrying a few long spines distally ; the hand expanding distally, 

 widest at the palm, strongly furred, also with scales over the breast ; the front margin 

 further produced than the hinder, and occupied at the apex with the usual pectinate 

 spines over-arching the small much-curved finger which is set close to this point ; the 

 concave palm is bordered with rather long cilia, and such also are found on the finger at 

 some little distance from the nail ; the palm being concave and the finger much bent ; 

 the latter will not be likely to close on the other without leaving a considerable canity. 



