410 VENERIDiE. 



controversy, whether that species is specifically distinct 

 from the one so designated by the British writers ; we 

 snbjoin, therefore, a brief digest of the more striking- 

 points of difference. The valves of gallina are always 

 more or less inflated, or at least ventricose, and their sur- 

 face covered with distant subimbricated grooves, which are 

 so peculiarly irregular as scarcely to be concentric (cha- 

 racters even more fully evident in the young than in the 

 old), their ventral margin is very strongly arcuated, and 

 their front dorsal edge short and much incurved ; internally 

 the hinder extremity, or the muscular scar, is almost in- 

 variably stained with purple ; the crenations are coarse, 

 and not particulai-ly numerous, and the sinus of the pallia] 

 impression is remarkably short. In striatula, on the con- 

 trary, the valves, whose shape is much more trigonal, are 

 frequently compressed, and very rarely are even ventri- 

 cose ; the surface, especially upon the umbones and in the 

 younger shells, is girt with distinct costellre, which are by 

 no means peculiarly irregular, and, if distant, change into 

 lamellae ; the arcuation of the lower edge is not remark- 

 able ; the front dorsal margin is long, and not strongly in- 



strige ; but in the only large specimen we have had an opportunity of examining, 

 scarcely any such markings were observed but where the old shell had been super- 

 ficially separated : the umbo is pointed and much reclined to one side, beneath 

 which is a broad cordifonn depression ; but neither this nor the cartilage slope 

 diflfers in colour from the rest of the shell, which is wholly of a dirty-white. In- 

 side white : hinge furnished with four teeth in each valve, but the outer one 

 above the cordiform depression in one valve is obsolete, or formed only by a 

 cavity for the reception of the corresponding tooth in the opposite valve : the mar- 

 gin is finely cremilated. Length (breadth) more than an inch ; breadth (length) 

 above an inch and a quarter. 



The above description is taken from a shell in the cabinet of Mr. Laskey, 

 who assured us he took it by dredging off the Isle of May, in the Frith of Forth, 

 in the year 1 804. In our cabinet is a single valve of about half the size of that 

 before described, which was found in Devonshire ; in this the longitudinal 

 striae are evident by the assistance of a lens, in the sulci between the tranverse 

 ridges." 



