EEPORT ON THE AMPHIPODA. 655 



First Perieopods. — Side-plates similar to the preceding pair. Branchial vesicles 

 very large. Marsupial plates narrow. First joint of the limb not reaching the lower 

 rim of the side-plate, with some setse on the hind margin, very long ones at the 

 apex ; third joint much longer and broader than the fourth, with long setiform spines at 

 the decurrent apex in front, and, like the preceding and following joints, with many 

 groups of them on the hinder margin ; the fifth joint longer than the fourth, with a few 

 groups of slender spines on the hinder margin, and some spinules on either side of the 

 hinge joint of the long, slender finger. 



Second Perseopods. — The side-plates very broad below, a little tooth at the hinder 

 extremity of the lower margin, and one facing it not far from the front extremit}^ of the 

 same. The limb similar to that of the preceding pair. 



Third Perieopods. — Side-plates with the front lobe descending below the hinder one. 

 First joint broadly oval, strongly spined on the very convex front margin, the hind 

 margin serrate, the lower margin smooth, rounded, descending below the back of the 

 second joint ; the third joint longer than the fourth, spined on both margins, inflated, 

 decurrent ; the fourth joint broader than the fifth, but scarcely so long, its lower margin 

 on the outside flatly rounded, broad ; all the five joints carrying spines and setiform 

 spines on the front margin ; the sixth joint or finger slender, unarmed. 



Fotirth Perseopods. — Branchial vesicles throwing out a narrow, accessory, sac-like 

 process from the upper part of the hinder margin. The joints similar to those of the 

 preceding pair, but broader and longer. 



Fifth Perseopods. — The first joint longer and very much broader than in the 

 preceding pair, very strongly spined on the front margin, more deeply serrate on the 

 hinder, and with the lower margin behind somewhat squared, not reaching below 

 the second joint ; the third joint scarcely dilated, spined at the decurrent apex behind 

 and just above the apex ; the fourth joint narrower than the third, shorter than the 

 fifths the spines in front of these joints shorter and stronger than those of the preceding 

 limbs. 



Pleopods. — Coupling spines minute, with two retroverted teeth just below the apex 

 on one edge and a backward serrature along the other edge ; four cleft spines on the 

 inner ramus of the first and second pairs ; the joints of the rami from fourteen to sixteen 

 in number. 



Uropods. — Peduncles of the first pair strongly spined, considerably longer than the 

 rami ; outer ramus longer than inner, with five spines along the border, stopping some 

 way short of the apex ; inner ramus with three spines ; peduncles of the second pair 

 not reaching so far back as those of the first, a little longer than the rami ; the rami 

 subequal, short, with few spines remote from the apex; peduncles of the third pair 

 shorter than the short stiliform rami ; outer ramus rather longer than inner, both almost 

 entirely unarmed. 



