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 ; 



