28 THE ELEMENTS 



plate 3d, figures 1st, 3d and 14th, 



ccc. 



Canal, or gutter, is a continuation 

 of the aperture, of those shells with a 

 beak, in which it forms a concave gut- 

 ter, running from its commencement 

 in the aperture, to the extremity. 

 Plate 2nd, figures 10th and 11th, Q Q; 

 plate 3d, fig. 8th, Q. 



Beak, or rostrum, is that lengthened 

 process in which the canal is situate ; 

 it commences a little higher up, on the 

 outside, than the insertion of the ca- 

 nal in the inside, which is always dis- 

 tinctly marked by the line of the aper- 

 ture. Plate 2nd, fig. 11th, P. 



Pillar, or columella, is that process 

 which runs through the centre of the 

 shell in the inside, from the base to 

 the apex in most univalve shells, and 

 appears to be the support of the spire ; 

 and, indeed, seems to form that part 

 of the shell ; it is in general grooved 

 or folded, and various other shapes ; 



