GLOSSARY. 207 



Valves, the diflferent pieces which compose the shell. 



Varix, Varices, longitudinal elevations or ribs, formed by the 



junction of the different additions the shell has received. 

 Ventricose, bellied. 



Vermiform, having the form of worms. 

 Vertex, the top or point of a shell. 



Umbilicated, having a hol<^ in the base of the pillar. 

 Umbo, the summit. 

 Undulated, waved. 



Whorl, a spiral convolution. 



riKis. 



