SILIQUARIA. 



Tetliya. These shells are seldom smooth on the outside, 

 but more commonly rough with small points, wherefore 

 one species has been called muricata, another jLhna, and a | 

 third spinosa. The S. anguina is remarkable for numerous 

 deep transverse furrows, which have the appearance of 

 being caused by the contraction of the shell in drying, and 

 which singularly resembles the contraction of the muscles 

 of a fish upon being scored : we can only account for such 

 an appearance, by supposing the parts of the shell that 

 present it to have been deposited in a soft or gelatinous 

 state, and afterwards to have hardened and contracted. 



In our plate we have given representations of three 

 specimens of the Siliquaria anguina : 



Fig. 1. Is taken from the fine specimen that lately formed part of the Tan- 

 kerville Collection. 



2 . Shows a regularly spiral specimen. 



3. A small and young specimen, in which state it has been called 

 Helix incisa by Linneans. 



4. Points to the opening in the principal specimen which has become 

 partly encrusted with a Cellepora. 



