1066 THE VOYAGE OF H.M.S. CHALLENGER. 



long as the basal part of the finger, on the inner margin of which close by is another 

 spine of almost equal length, and needle-like. 



The triturating organs of the stomach show on one side about fifteen strong spines, 

 wearing something the appearance of a set of Pandean pipes, but a little bent ; on the 

 other side are numerous slender spines. 



First Gnathopods. — The side-plates wider below than above, the lower front corner 

 being produced over the basal joints of the lower antennae. First joint reaching beyond 

 the side-plate, a little curved, the front concave margin having some spinules, the 

 convex hind margin seven long seta? on the central part, besides some slender spines ; 

 four long setae high up on the surface project beyond the front margin ; the second 

 joint is short, with several long spines at the apex behind ; the third joint has convex 

 sides converging to an acute apex, with long spines on the lower part of the hind 

 margin and on the inner surface across the apex ; the wrist is rather longer than the 

 hand, fringed along the hind margin and at the front apex with many long spines, of 

 which there are some also on the surfaces, chiefly on the inner ; the hand oval, 

 narrowing towards the hinge of the finger, the palm minutely pectinate, occupying 

 more than half the hind margin, set with various spines ; the two surfaces of the hand 

 also are armed with many groups of spines ; the finger is more than half the length of 

 the hand, rather broad, curved, chiefly at the nail, which reaches just beyond the palm ; 

 the inner margin of the finger cut into seven decurrent teeth, and carrying a few small 

 setules ; the dorsal cilium rather long, placed very near the hinge. 



Second Gnathojwds. — Side-plates oblong, with rounded corners. Branchial vesicles 

 narrow, not quite so long as the side-plates. The marsupial plates longer than the 

 branchial vesicles, widening a little from the basal part, and fringed with sixteen setae. 

 The first joint reaching beyond the side-plates, the front margin straight, with a seta 

 near the apex, the hind margin somewhat sinuous, armed with a few setiform spines ; 

 the second joint short, with one or two apical spinules ; the third rather longer and 

 more acute than in the first gnathopods, but similarly armed ; the wrist shorter than 

 the hand, distally broad, cup-like, with a few spines at the front apex, and many on the 

 rounded corner behind as well as on the lower margin of the inner surface ; the hand 

 large and broad, the front margin gently convex ; the hind margin, which is slightly 

 serrate and set with spines, is almost straight and longer than the oblique palm, over 

 which the finger closes as in the first pair ; there are several surface groups of spines ; 

 the finger is dentate on the inner edge. In the male the first joint is much more 

 dilated, and the hind margin of the hand is produced into a tooth carrying a palmar 

 spine at the commencement of the palm, which is excavated. 



First Per&opods. — Side-plates and branchial vesicles similar to the preceding pair. 

 The first joint considerably longer than the branchial vesicle, straight, gradually dilated 

 distally, with some long setae at parts of both margins, those on the hind margin near the 



