VELUTINA. 351 



Lamellaria perspicua in shape, and of a Succinea in colonv 

 and texture. It is glossy, transparent, and so membrana- 

 ceous as to permit of much indentation without fracture, 

 though its substance is extremely thin ; and is of a greenish 

 amber hue, with a slight disposition to nacre internally. 

 The shell, whose shape is obliquely oval, and broader than 

 long, appears so much depressed when placed on its mouth, 

 as to be considerably less than a hemisphere, although the 

 body is much swollen (the swell diminishing, however, 

 towards the laterally produced lip), this seeming flatness 

 results chiefly from the peculiar basal recedence of the 

 pillar lip. The surface, though not distinguished by any 

 prominent sculpture, is not quite smooth, but exhibits both 

 wrinkles and waves of growth, besides some faint indica- 

 tion of depressed spiral costas, which are most perceptible 

 in the middle of the final whorl. The spire, comprehending 

 barely a single volution, whose nucleus is blunt and large, 

 is scarcely, if at all, raised above the top of the very ample 

 body, to which it is placed laterally, occupying a very small 

 portion of the breadth of the shell. Both turns are simple 

 in their convexity (devoid of any retusion or flattening of 

 surface) and are divided by a simple but profoundly im- 

 pressed suture, towards which the margin of the body- 

 whorl, whose basal declination is not planulate, bends 

 convexly inward. The aperture is most capacious, filling 

 more than three-fourths (usually indeed five-sixths) of the 

 ventral surface, and rising almost to the level of the apex 

 of the spire. The general contour of the mouth is obliquely 

 subrhomboidal, the basal portion of the very sinuous pillar 

 lip is comparatively straight, and forms rather more than a 

 right angle with the straightish anterior portion of the 

 outer lip, that runs almost parallel to the upper end of the 

 inner lip, where the swell of the body is so trifling as 



