NOMENCLATURE. 2 1 



retuso-umbilicata. Retuso-umbilicate , the spire 



being so much impressed as to seem rather 



concave than convex. 

 Suture. Sutures of the whorls; the spiral 



line of connexion between them. 

 duplicates. Duplicate ; with a double elevated 



line or stria. 

 marginata. Marginate ; raised, with a promi- 

 nent keel. 

 Testa. Shell. 

 antica. Anterior (part) ; that which is towards 



the spire. 

 clavata. Clavate ; club-shaped, thicker above and 



elongated towards the base. 

 convoluta. Convolute; when the exterior whorls 



spirally involve the interior. 

 corticata. Corticate ; covered with an epidermis. 

 cylindrico-umbilicata. Cylindrically umbilicate ; 



the umbilicus of which is a cylindric cavity. 

 emarginata. Emarginate; having the margin 



excavated by a sinus. 

 exumbilicata. Imperforate ; destitute of a hollow 



umbilicus. 



