36 GL O. Sars. 



Description of the female. 



The length of the specimen examined, which is a fully 

 grown ovigerous female, measures 0,63 mm., and is accord- 

 ingly somewhat inferior to that of both the above-named 

 European species. 



Seen laterally (fig. 1), the shell exhibits an oval quad- 

 rangular form, with the greatest breadth about in the middle. 

 The hind extremity is obliquely truncated, and not nearly 

 so broad as in A. qvadr angularis, and with the inferior comer 

 the more prominent. The dorsal margin forms a perfectly even 

 curve until the tip of the rostrum, and joins the hind edge 

 without any distinct intervening angle. The inferior edges 

 of the valves are nearly straight and horizontal, though 

 slightly ascending in front to the anterior corners. Behind, 

 they join the posterior edges by a rather sharp but perfectly 

 even curve. The head is somewhat procumbent, not nearly 

 so erect as in the 2 European species, and terminates in 

 an acute, somewhat hooded rostrum. 



The surface of the shell is sculptured with well-marked, 

 and rather closely set, longitudinal striæ, about 20 on each 

 side. These striæ are more conspicuous in the posterior 

 part of the shell, disappearing gradually in front. The infe- 

 rior edges of the valves are throughout fringed with deli- 

 cate bristles. 



The eye is well developed, exhibiting some few very 

 conspicuous crystalline bodies. 



The ocellus is comparatively large, almost attaining the 

 size of the eye, and occurs somewhat nearer to it than to 

 the tip of the rostrum 



The antennulæ are rather narrow and sub fusiform, and do 

 not quite extend to the tip of the rostrum. They are pro- 



