CATECHISM OF CONCHOLOGY. 19 



size and thickness of the tooth, than by any assign- 

 able form. 



In a few instances the hinge is destitute of a 

 tooth, and the shell is only to be classed by other 

 points of generic resemblance. 



Q. Are the animal inhabitants of the Mya at 

 all peculiar in their habits ? 



A. They burrow in the sand or mud, leaving 

 a channel through which they thrust a slender 

 proboscis, for the purpose of obtaining clear 

 water. 



Q. Does not a species of the Mya produce 

 pearls ? 



A. Yes. The Mya Margatifera, an inhabitant 

 of many of our own rivers, the Conway espe- 

 cially, which was anciently celebrated for its 

 extensive pearl fisheries.* 



Conchologist's Companion. 



