235 



which is somewhat reflected and cuspidate ; and constitutes, as it were, 

 the apex or summit of the pyramid : the back, or that part of the valve 

 proceeding from the margins, rounded : the opposite side flat, consisting 

 of the hinge and foramen described. The other valve semicircular, 

 moderately convex, broad ; its beak prominent, pointed, and incurved 

 over the base of the foramen." 



The specimen represented Plate XVI. Fig. 17, differs from that figured 

 by Mr. Martin, only in the beak of the conic valve not being so much 

 reflected. On the upper part of this figure is the semicircular valve, 

 with the convex wave on its back, a, terminating forwards in the pro- 

 minent, pointed beak, incurved over the base of the foramen. On the 

 lower part is the conic valve, which has on its back part, but which could 

 not be here shown, a deep rounded sinus, its base joining the base of the 

 convex wave on the semicircular valve at a, and terminating in a point at 

 the bottom, where it meets the point of the perpendicular triangular 

 foramen at b, in the apex^ or what must rather be considered as a beak, 

 though not so formed. 



This ingenious naturalist observed, that the species A. subconicus united 

 this species with the more common straight-hinged perforated anomitae; 

 but added, that in another shell, which he had not yet named or 

 described, the hinge is still less ; and the beak of the large valve, instead 

 of being straight, is somewhat incurved, and therefore more strictly 

 united the species. As Mr. Martin's collection is now dispersed, there 

 is little reason to expect that the figure of this shell will be published; 

 it is therefore with pleasure I find myself able to give a representation 

 of a shell which seems to possess all the characters of that of which he has 

 spoken. 



This shell, Plate XVI. Fig. 16, is of a roundish trigonal form, with 

 two convex, longitudinally-furrowed, valves ; the furrows being rounded. 

 The hinge straight, extended, and very patulous, with a large triangular 

 pit or foramen, between the beaks of the two valves. The beak of the 

 large valve, at the point of the foramen, at b, unlike that of the preced- 



