OF CONCHOLOGY. 61 



shells, stones, and other extraneous 

 bodies at the bottom of the sea : they 

 are generally affixed by a ligament 

 which passes through the perforation 

 in the flat valve. A species called the 

 Squamula is often found adhering to 

 the Pecten Opercularis, and is very 

 common at Aberlady Bay in Scotland ; 

 it resembles the scale of a fish, and 

 partakes of the form of the furrows and 

 striae of the Ostrea, which makes it 

 very beautiful. 



Lamarck has divided the Anomia 

 into three genera : Anomia, Calceola, 

 and Crania. 



The Anomia Sandalium of Linne, 

 is an example of the Calceola, and the 

 Anomia Craniolaris of the Crania. 



In Turton's Linne fifty-one species 

 are described ; and six have been dis- 

 covered on the British shores. 



Genus 16th- MYTILUS, (or mus- 

 cle.) Animal allied to an Ascidia ; 

 $hell bivalve, rough, generally affixed 



