34 CATECHISM OF CONCHOLOGY. 



shell greater than its breadth), toothed on both 

 sides. This genus is remarkable for the high polish 

 which adorns it in its native state. 



Q. Are the instincts of the animal inhabitant 

 at all peculiar ? 



A. A very remarkable property has been 

 ascribed to this shell-fish, namely, the power of 

 quitting his tenement, and forming one more 

 suited to his necessity. They live deeply buried 

 in the sand, from whence, it is said, these little 

 wanderers, crawl forth to expatiate upon the 

 rocks, leaving their shells behind them for the 

 benefit and instruction of conchologists. 



CHAP. XXV. 



UNIVALVES: 

 BULL A ; Dipper, or Bubble. 



Q. WHAT have you to tell me respecting the 

 Bulla ? 



A. That the shell is convolute and unarmed 

 with teeth ; that the aperture is oblong, longi- 

 tudinal, and entire at the base; and that the 

 columella is oblique and smooth. It is, however, 



