REPORT ON THE AMPHIPODA. 1231 



little teeth or spines, and a spinule or two on a little indent near the top of the inner 



margin. 



Maxittipeds. — Inner plates small, not reaching the apex of the first joint of the 

 palp, not strongly armed ; the outer plates small, reaching little beyond the inner, 

 about level with the apex of the first joint of the palp, the distal part of the inner 

 margin serrate, armed with a few spinules ; the first joint of the palp scarcely longer 

 than its distal breadth ; the second joint about twice the length of the first, broad, 

 with slender spines on the inner margin ; the third joint not much shorter than the 

 second ; the finger as long as the third joint. 



First Gnathopods. — First joint as long as the hand, but narrower, widening a little 

 distally ; third joint a little longer than the second, with half-a-dozen slender genicu- 

 late spines across the inner surface, the middle of the convex hind margin furred, the 

 front apex acute, resting on the wrist ; the wrist much longer than the third joint, 

 shorter and much narrower than the hand, the front margin smooth, the hinder furred, 

 the inner surface carrying many slender spines ; the hand widening from the base to the 

 apex of the short hind margin, which is partly furred, the adjoining surface being 

 microscopically marked with lines of pectination, the apex itself forming a strong denti- 

 culate tooth-process carrying setules and a palmar spine ; from the cavity of this process 

 rises on the inner surface a much smaller triangular process, also carrying a palmar 

 spine ; from this point to the narrowed apex of the hand the long convex palm, which 

 almost usurps the place of the hind margin, is planted with numerous small spines and 

 a few setules ; the front margin is smooth, not very convex, with four transverse 

 rows of long graduated spines on the adjoining surface ; the finger is as long as the 

 palm, slender, curved, with a very small dorsal cilium close to the base, and some cilia 

 or hairs near the smooth inner margin. 



TJie Second Gnathopods much larger than the first, especially in the male, in which 

 the hand is immensely dilated ; in structure the second gnathopods much resemble the 

 first, except in regard to the wrist, which is here scarcely longer than the third joint, 

 almost coalescent with the hand, to which it forms a very narrow base ; the finger is 

 bulky in some proportion to the size of the hand, having in the Challenger specimen of 

 the male a small incurving of the inner margin near the base. The male specimen was 

 defective beyond the second segment of the peraeon. 



First Perseopods. — Side-plates small, but veiy distinct, much broader than deep. 

 Branchial vesicles small, a narrow oval. Marsupial plates large, the fringing setaa 

 small. The limb very slender, first joint nearly as long as the segment ; second slightly 

 narrower than the first, little longer than broad ; third longer than the fourth, the two 

 together about as long as the first ; the fifth a little longer than the fourth, scarcely 

 narrower ; the finger slender, tapering, curved at the acute tip, nearly as long as the 

 fourth joint. 



