NOMENCLATURE. 3? 



retusO'Umlilicata. Retuso-umbilicate ; the spire 

 being so much impressed as to seem rather 

 concave than convex. 



SuTURiE. Sutures of the whorls ; the spiral 

 line of connexion between them. 



duplicates. Duplicate, with a double elevated 

 line or stria. 



marginatcB. Marginate ) raised, with a promi- 

 nent keel. 



Testa. Shell. 



antica. Anterior (part) ; that which is towards 

 the spire, 



clavata. Clavate 3 thicker above and elongated 

 towards the base. 



convoluta. Convolute ; when the exterior whorls 

 spirally involve the intei'ior. 



corticata. Corticate ; covered with an epidermis. 



cylindrico-umbilicata, Cylindrically umbilicate ; 

 the umbilicus of which is a cylindric cavity. 



emarginata. Emarginate ; having the margin ex- 

 cavated by a sinus. 



exumbilicata. Imperforate ; destitute of a hollow 

 umbilicus. 



