PLATE XXI. 



the shell is naturally covered when in a living state. From this 

 figure it will be perceived that the direction of the spiral wreath or 

 whorls in the larger shell is exactly reversed, and that the mouth or 

 aperture of the shell, which in the smaller figure appears on the right 

 side, is seen in the reversed shell on the left. Thus upon the least 

 comparison of the two figures, the true character of the reversed shell 

 will be distinctly perceived. 



We should not omit to mention that the smaller figure which 

 represents the unreversed shell would appear of the same pallid hue 

 as the reversed shell, upon the removal of the epidermis with which 

 it is enveloped. Sometimes, however, when this common kind is 

 particularly fine, the exterior surface is delicately tinged with a less 

 pallid hue, and the pillar lip and opening yellowish, inclined to flesh 

 colour. That particular kind or variety which in England is deno- 

 minated the low spired or heavy Turnip Shell, is sometimes pleasingly 

 diversified with more vivid tints, and the younger shells occasionally 

 spotted with brown, upon a ground tinged with yellowish or buff 

 colour. We have no knowledge of any reversed shell of this latter 

 kind, excepting one which is in the Museum at Copenhagen. 



