REPORT ON THE AMPHIPODA. 1339 



margin microscopically pectinate, having a spine at the apex, the distal margin finely 

 pectinate, projecting behind the hand ; the hand narrow, finger-like, a little curved and 

 tapering, the distal end rounded, but with a little setule-carrying indent, microscopically 

 pectinate, produced over the base of the small finger in the same way that the trunk 

 of the finger is produced over the base of its own acute nail ; the nail is nearly as long as 

 the trunk of the finger. 



Second Gnathopods a little longer, but narrower than the first. The first joint 

 narrower, not much longer, than in the preceding pair, as long as the four following- 

 joints together ; the second joint a little longer than broad ; the third a little longer 

 than the second, with parallel margins, unarmed; the wrist not half the length, about 

 half the breadth of the first joint, longer and broader than the hand, nearly straight and 

 smooth ; the hand narrow, tapering, longer than the hand of the first gnathopods, 

 produced in two delicate transparent plates beyond the base of the finger's nail, the 

 plates finely serrate on the inner edge, but the serration is not easy to observe ; the 

 finger small and slender, the extremely acute nail shorter than the trunk of the finger, 

 with a minute setule at the base on the inner margin. The fingers of the second 

 gnathopods face the mouth-organs, while those of the first have the ordinary position. 



First Peraeopods. — Branchial vesicles small, oval, not half the length of the first joint. 

 The limb much longer and broader than the second gnathopods, the first joint about as 

 long as the third and fourth together, smooth-edged, the second rather longer than 

 broad, the third about once and a half as long as the second, the fourth nearly three 

 times as long as the third, having some setules along the almost straight hind margin ; 

 the fifth joint more slender, slightly curved and tapering, together with the finger equal 

 in length to the fourth joint ; the finger small, acute, a little curved. 



Second Perseopods. — Branchial vesicles larger than in the preceding pah', the limbs 

 similar. 



Third Perseopods. — Branchial vesicles larger than in the preceding pair. The joints 

 of the limb, with the exception of the finger, rather stouter and a little longer than in 

 the second peraeopods. 



Fourth, Perseopods. — Branchial vesicles subequal to the preceding pair, the limb a 

 very little shorter. 



Fifth Perseopods. — The limb considerably shorter than the preceding pairs, the 

 difference affecting all the joints except the first, but especially the fourth and fifth, 

 which together are not equal in length to the first, instead of being, as in all the other 

 peraeopods, much longer than it ; the fifth joint shorter and much narrower than the 

 fourth, curved, tapering ; the finger small, nearly straight, acute. 



Pleopods. — The peduncles massive, in the first two pairs longer than the rami ; the 

 two coupling spines have the base bulbous, the shaft feathered with from three to five 

 retroverted teeth on each margin, and the apex crescent-shaped ; in the cleft spine of the 



