216 ROBERT H. wolcott: 



passing beneath the anterior margin of III. Of the posterior group, III 

 comprises about one-third and the suture between it and IV runs obliquely 

 inward and forward half way to the inner margin. Anterior margin 

 slightly concave, inner and posterior slightly convex, with inner posterior 

 angle rounded and those of opposite sides diverging. In the male all the 

 epimera relatively much larger and the inner ends of the anterior groups 

 nearly in contact. The posterior groups are not only nearly in contact 

 but a chitinous bridge connects the two which thus become one mass 

 which is somewhat emarginate posteriorly. 



The legs are all longer than the body in the female and very much 

 longer in the male. Ill is the shortest, I next longer, II next and IV the 

 longest of all. They are of medium stoutness and taper slightly from 

 base to tip. In I and II the three outer segments are, in order of length, 

 beginning with the longest, 4, 5, 6; in III all are nearly equal, but 5 exceeds 

 4; and in IV, 6 is also longer than 4. The spines are moderately 

 numerous on the legs of the female and are rather long, while those on 2, 

 3 and 4 of I are set into short excavated papillae similar to those of A. 

 crassipes, though not so prominent. A bunch of four or five spines on 

 the proximal half of the ventral surface of I 4 is noticeable. On the 

 ventral surface of 4 and 5 of both III and IV, there are numeroas hairs, 

 more abundant and smaller on IV than on III, longer at the tip of each 

 than elsewhere. The legs of the male posess fewer spines than do those 

 of the female, and in this sex IV is peculiar; 4 of this leg is curved, the 

 concavity being on the posterior and ventral aspect of the segment, and 

 at the tip on the same aspect is a bunch of very long spines. On the 

 posterior surface of 5 and about the middle is a bunch of strong, feathered 

 spines. The claws are similar in form to those of A. ypsilophorus, and 

 as in that species, are received into a cleft in the end of the dilated tip of 

 the segment. 



The genital area is proportionately large and flanked in the male by 

 one plate on each side, in the female by two. Each of the two in the male 

 is broadly lunate in form and bears five acetabula in two groups — 2 and 3 

 respectively — and numerous small spines. In the female the anterior 

 plate on each side is rhomboid in shape, with the anterior and outer mar- 

 gins slightly convex, and the posterior concave; it bears two acetabula, 

 which are larger than those of the male, and its inner margin is reflected 

 outward, forming two blunt, moderately thick lips, the margin of each of 

 which bears two short stout spines. The posterior plate is roughly circular 

 with a projecting inner anterior angle and its anterior and inner margins 

 are thickened, the inner also reflected, forming a broader and less promin- 

 ent lip than that of the anterior plate, while at the inner anterior angle 

 is a stout spine, and external to it on the anterior margin a second. On 

 this plate are three acetabula. 



