NOMENCLATURE. 45 



species of the Genus Anomia adhere to 

 foreign substances. 



Labia. Lips. 



interna. Internal ; the small lips within the li- 

 gament^ which are united by it. 



hianiia. Gaping; when the lips are wide, or 

 distant from each other. 



retracta. Retracted ; opposed to prominent. 



truncata. Truncate 5 shorter than the suture. 



externa. External ; the margins of the area, or 

 anterior slope about the ligament. 



ineumbentia. Incumbent; when one of the ex- 

 ternal lips hangs over the other. 



LiGAMENTUM. LiGAMENT ; a cartilage which 

 closes the suture, and is affixed between 

 the internal and external lips of the shell, 

 connecting the valves. 



LiMBUS. LiMBUs; circumference within the 

 margin. 



LoNGiTUDo. Length, measuring from the sum- 

 mit to the opposite margin; and the 

 breadth, Latitudo, in a direction at right 

 angles to this. 



