360 Dr. S. J. Hickson on a new Species 



The middle branch is more oval in shape and bears on its 

 inner margin a dense row of short thorn-like hairs. The 

 inner branch is semicircular in outline and bears a number of 

 stiff, finely feathered hairs, one row arranged directly on the 

 margin and one or two smaller rows on the under surface. 



The second maxilla3 (fig. 5) are also thin, delicate, folia- 

 ceous appendages. The protopodite is trilobed and bears a 

 large number of long, delicate, but at the same time stiff 

 hairs. The ovoid anterior end of the scaphognathite bears at 

 its margin a few thick feathered hairs. The posterior end of 

 the scaphognathite bears a tuft of remarkably long set^e ter- 

 minated by a small hook. These long sette are found in this 

 position in all the species of the genus Atya. It is usually 

 supposed that they are for the purpose of keeping the gill- 

 chamber clean. 



The first maxillipedes (fig. 6) are ahnost identical with 

 those of Atya hisuJcata. The inner margin is fringed with 

 very long delicate hairs. 



The second maxillipedes (fig. 7) also do not offer any very 

 remarkable peculiarities. The outer border of the terminal 

 joint being bent through an angle of 180° comes to face in- 

 wards, and is covered with a dense brush of very fine delicate 

 hairs. The other joints are sparsely covered with stiff 

 hairs. There is a broad mastigobranchial plume supporting 

 a gill and a well-marked podobranch as well. 



The third maxillipedes (fig. 8) are long and pediform. 

 The basal and first joints of the endopodite are sparsely 

 covered with long delicate hairs, the second joint bears a few 

 short stiff bristles, the last joint bears a brush at the proximal 

 end of fine close-set hairs, but more distally they become 

 shorter and stiflfer, until they become almost tooth-like at the 

 extremity. The exopodite has a number of long delicate 

 hairs towards its distal extremity. 



On the basal joint there is a rudimentary mastigobranch 

 and a well-developed arthrobranch. 



Of the ambulatory limbs (pereiopods) the first two are 

 chelate, the second pair being somewhat longer than the first 

 pair. The carpos of the first pair is short and shaped like 

 an elongated heart. The articulation with the propodos lies 

 on the inner side of the lower angle of the distal extremity 

 of the carpos. The propodos does not extend behind as well 

 as in front of the articulations. The tuft of hairs at the ex- 

 tremity of the dactylos and propodos is very dense, and pro- 

 tects a sharp curved hook. Each of the hairs of these tufts 

 bears a number of fine recurved hairlets, so that each tuft is 



