390 MRS. E. W. SEXTON ON A [Apr. 28, 



deeply curved and hollowed, forming the lower portion of the 

 oral tube ; the second joint of the one maxilliped is fused with 

 that of the other for more than two-thii-ds the length. Inner 

 plates narrow, linguiform, tipped with two spinules ; outer plates 

 large, hollowed, so close together as to conceal the inner plates, 

 armed on the inner edge with ten uncinate spinnles. 



The jjalp is geniculate at the middle. The 1st joint is the 

 shortest, broad distally ; the 2nd and 3rd successively longer ; the 

 4th considerably the longest of all, being twice the length of 

 the first, lanceolate, one setule apically, finely serrated on both 

 margins, the serrations being stronger on the inner edge. 



8et(B. — The 1st joint has one small seta at the iriner angle ; 

 the 2nd cairies three long sette on its outer angle ; the 3rd has 

 one proximally inside the margin on the outer surface, two 

 clusters on the mai-gin, and a fringe of six around the outer 

 angle, with three on the inner angle. 



In the young (fig. 7) the 3rd joiiot is the longest ; the 2nd and 

 4th subecjual to each other in length. 



The 1st joint has one small seta ; the 3rd carries one at each 

 distal angle, while the 4th has the apical setule and the mai-gins 

 not serrated. 



First Gnathopod.— .4f^«/i5 (PI. XIX. fig. 8). The 2nd joint 

 is very long, slightly curved, widening a little at the distal end ; 

 the 3rd and 5th ai'e subeqiial in length ; the 4th is the 

 smallest, greatly curved, the outer margin of the joint being 

 five times as long as the inner. The 6th joint or " hand " is bent 

 over to such an extent that the ai-ticulation of the finger, 

 normally situated at the infero-anterior angle, appeal's to oi'iginate 

 from the infero -posterior corner instead, and what would 

 normally be the under surface thus becomes the upper. The 

 curve backwai'ds is so extieme that this articulation almost 

 touches the third joint, and the fourth and fifth are nearly hidden 

 on the outer side. The hand is enormously developed, rounded- 

 triangular, gi'eatly inflated, more so on the uj)per side. The 

 palm margin is straight Avith 1 5 strong recurved teeth, gradually 

 decreasing in size posterioi-ly. At the exti'eme anterior angle is 

 a small groove into which the tip of the " finger" fits. On the 

 uppei' edge of this groove ai-e two sti'ong spines ; on the under 

 edge thi-ee spines, with large tubei'cles at the bases of two of 

 them. One of these spines is minute, one broad and strong, 

 similar to the uj^pei- ones ; and the third, strong, tapering, mobile, 

 is situated at the anterioi-end of the row of teeth, reaching, when 

 close against the palm, to the base of the sixth tooth. The 

 " fingei- " oi- claw is lai'ge and cui-ved, not extending beyond the 

 palm margin. There are no seta? on any of the joints. 



Immature (PI. XIX. fig. 9). — The second joint is much more 

 curved than in adult. The hand sets out moi'e, at right angles 

 to the other joints. The small teeth numbei- 15, the posterior 

 five being bai'ely visible, and thei'e ai-e two vei-y lai-ge mobile spines 

 at the anterior' angle and two smaller just appearing. 



