ELEMENTS 



CONCHOLOGY. 



INTRODUCTION. 



CoNCHOLOGYor Testaceology is the science which 

 treats of the stracture, appearance, properties, and 

 methodical arrangement of Shells, the external 

 testaceous covering of certain molluscous animals. 



Testacea constitute the I lid Order of Vermes, 

 the Vlth Class of the Linnaean System of Nature. 



This order includes all shells of a calcareous na- 

 ture, that is, composed of carbonate of lime mixed 

 with some gelatinous matter; and excludes those 

 which are called crustaceous, in the covering of 

 which phosphate of lime is a constituent part. 



