66 TELL IN A. 



if the anterior slope be compressed into an acute 

 wedge-shaped form, or if it be crooked. But 

 the primary teeth are still in either case to be at- 

 tended to ; for they constitute the best, though not 

 always the most obvious, criterion. 



It is worthy of remark, that the bend or fold of 

 the extremity of the compressed slope is, without 

 any exception, towards the left valve ; that is, to- 

 wards the right hand of the observer when the 

 shell is placed upon its base with tiie area in 

 front. 



The Tellinse are found buried in the sand or fine 

 gravel of the sea shore, some of them in rivers or 

 wet ditches. TsAeo), from whence Tellina is form- 

 ed, places but an ill defined limit to the tribe, as 

 it will include all shells which arrive quickly at 

 maturity/. It is difficult to imagine why the name 

 was originally adopted, or why it has been retained 

 by almost all Conehologists. 



