GLOSSARY. 7 



the point divided into two ; longitudinal , when it extends 

 along the margin. 



Tubercle, a protuberance or knob. 



Tuber culated, having elevations resembling warts. 



Tubular, (applied to Multivalves), when the greater part 

 of the shell is cylindrical. 



Turbinated, when the belly of the shell is large in propor- 

 tion to the spire, which seems to proceed from the cen- 

 tre. 



Valves, the different pieces which compose the shell. 



Varix, Varices, longitudinal elevations or ribs, formed by 

 the junction of the different additions the shell has re- 

 ceived. 



Ventricose, swollen. 



Vermiform, having the form of worms. 



Vertex, tlie top or point of a shell. 



Umbilicated, having a hole in tlie base of the pillar. 

 Umbo, the summit. 

 Undulated, waved. 



Whirl, a spiral convolution. 



