356 VELUTINID^. 



posed of not quite three turns, of which the final one 

 occupies nearly the entire area, since the spire is scarcely 

 elevated, and the breadth of the penult turn is merely the 

 eighth of that of the body-whorl, so extremely rapid is 

 the increase, in both directions, of the volutions. When 

 resting on its mouth, the shell seems greatly depressed, 

 not being even hemispherical ; yet this depression is rather 

 apparent than real (for the surface of the whorls is well 

 rounded), and results from the extraordinary recession of 

 the pillar lip. The basal declination of the body is abrupt, 

 but not at all j^lanulate, and that portion of the ventral 

 surface, which flanks the aperture on the left, is well 

 rounded, and though narrow, not so much so as in tentacu- 

 lata. The penult turn rises with moderate abruptness and 

 some slight elevation, and even the tiny apical nucleus is not 

 quite flattened. The simple suture is well defined through 

 the convexity of the whorls, and is neither preceded nor 

 succeeded by any canaliculate retusion. The immense 

 aperture, which discloses the whole of the internal gyra- 

 tion, is not very much broader than long. The course of 

 the outer lip is almost semicircular ; its chief swell is rather 

 below the middle. There is not the slightest vestige of 

 any umbilicus, the pillar lip being acute and not at all 

 reflected. The sinuation of the inner lip is very curious ; 

 it swells out a little at first beneath the spire, is then most 

 profoundly incurved, and finally shelves very slowly down- 

 wards in a comparatively straight line. Few individuals 

 measure more than two-thirds of an inch at the greatest 

 width. 



Montagu was the first naturalist who described and 

 figured the animal of this species ; and as considerable 

 doubt hangs over the determination of its European con- 

 geners, we transcribe his account. He states that the 



