X GLOSSARY. 



HinffCf the part where the valves are united, and gene- 

 rally furnished with one or more teeth: it is said to 

 be compressed, when it is formed of one compressed 

 tooth : lateral^ when placed on one side of the shell : 

 refiectedi 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 to this part. 



Hispid, covered with hairs, as in the Helix Hispida. 



Imbricate, when the surface is covered with scales parti- 

 ally over-lapping 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 Patellae, 



Keeled, see Carinated. 



Labium, see Lip. 



Lenticular, when the valves are round, and diminish in 



thickness from the centre towards the edges. 

 Lid, see Operculum. 

 Ligament, a membranous substance which connects the 



valves: it is both interior and exterior in the generality 



of Bivalves. 

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



breadth, and its form not cylindrical. 

 Linguiform, tongue-shaped. 

 Lip, (in Univalves), the sides of the aperture: (in Bivalves), 



the exterior edge of the valves. 



