Xll GLOSSARY. 



when its edges are folded over the exterior margin : 

 terminal, if situated at the extremity of the shell: and 

 truncated^ if the beaks of the shell appear to have been 

 transversely cut off and the teeth of the hinge fixed in 

 this part. 

 His})idf covered with hairs, as is the Helix Hispida. 



Imbricate, when the surface is covered with scales over- 

 Japping each other. 



Imperforate, having no umbilicus. 



Inequilateral, when the anterior and posterior parts of 

 the shell are dissimilar. 



Inequivalve, when the valves are dissimilar. 



Involute, without a spire, as in the Patellie. 



Keeled, see Carinated, 



Labium, see Lip. 



Lenticular, w hen the valves are round, and diminisli in 

 thickness from the centre towards the edges. 



Lid, see Operculum. 



Liyament, a membranous substance which connects the 

 valves: and is prickly : punctated, marked with small 

 cavities : scaly : or smooth. It is interior and exterior 

 iu the generality of Bivalves. 



Linear, when the length of the shell is greater than its 

 breadth, and its form not cjliiidrical, 



Liuf/^i^ifoi'vi, tongue-shaped. 



Lip, (in Univalves), the sides of the apertures : (in Bi- 

 valves), the exterior edge of the valves. 



Lunar or Lunate, having a circular form. 



Margin, the edge of the shell: anterior, (he space m 



