AMPHIPODA. 29 



First maxillae normal. 



Maxillipeds as in I. pacijica, except the inner plates, which are oblong and almost 

 as wide as the outer. 



First gnathopods : First joint widest in the middle ; wrist rather shorter than the 

 hand, which is chelate with short spines on the immovable digit. 



Second gnathopods : First joint narrow, oblong, as long as the remaining joints ; 

 wrist and hand subequal, the latter chelate with long plumose setae on the hind 

 margin. 



First and second perseopods : First joint strong, widening distally ; second as long 

 as the foui'th ; third rather longer and produced behind. 



Third perseopods : First joint oblong, with a median ridge and five subequal teeth 

 on the hind margin. In young specimens the spines are fewer and less equal. The 

 side-plates are wider than deep, with a tooth directed backwards. 



Fourth perseopods: First joint rather wider than in the third pair, with fewer 

 and more unequal teeth, and the posterior angle very acute and upturned. 



Fifth perseopods: Side-plates small. First joint wider than in the fourth pair, 

 with four unequal teeth on the hind margin, and the posterior angle still more acute 

 and produced. 



First uropods : Rami subequal, shorter than the peduncle. 



Second uropods : Outer ramus two-thirds of the length of the inner which is rather 

 shorter than the peduncle. 



Third uropods : Eami wide-lanceolate and subequal, longer than the peduncle. 



Telson emarginate, the outer angles reaching to the end of the peduncle of the 

 third uropods. 



The nearest ally of this fine species is /. pulchridentata, Stebbing, from Heard 

 Island, from which it differs in not having the lower ends of the first three pairs of side- 

 plates forked, and in the numerous dorsal spine-like teeth on the seventh mesosome and 

 three pleon-segments. 



I. LONGIPES. (PI. 9, fig. 17.) 



/. longipes, A. 0. Walker, Ann. and Mag. Nat. Hist. XVIII. (1906), p. 151. 



Coulman Island, 100 fm., 13 Jan., 1902 ; one, length 30 mm. (not dissected). 



Mesosome wide ; pi eon and urus compressed. Head, exclusive of the rostrum, 

 longer than the first segment ; rostrum fully as long as the rest of the head, deflexed 

 and pointed ; ocular lobe rounded in front and terminating below in a strong tooth 

 directed downwards. Eyes round-oval, dark, widely separated. 



First segment considerably longer than the second (which is the shortest of all) and 

 subequal to the sixth ; third, fourth, and fifth shorter than the first and subequal ; 

 seventh as long as the fifth and sixth united, with two long subdorsal teeth directed 

 backwards. The first side-plates are rather deeper than the segment, much expanded 

 below and rounded ; second and third bluntly pointed ; fourth sharply pointed below. 



