NOMENCLATURE. 15 



scrobiculati. Scrobiculate ; covered with small 

 pits or excavations. 



scripii. Lettered ; marked with various charac- 

 ters resembling letters. 



sinistri. Left-handed ; heterostrophous, turning- 

 round the pillar from right to left, in- 

 stead of pursuing their usual, opposite, 

 course. 



spinoso-radiati. Spinosely radiate ; beset with 

 spines in a circle, either concatenate, 

 united at their bases, or setaceous, like 

 bristles. 



striati. Striate ; encompassed with very fine 

 raised or excavated lines : punctate striae 

 are those which have elevated or impressed 

 points placed along them ; the points may 

 lie concatenate, strung like beads, or jyer- 

 iuse, deeply excavated. 



sulcati. Sulcated ; marked with broader lines, 

 either hollow, ridged, or elevated. 



Apertura. Aperture, Mouth; the orifice, 

 entrance, or opening of the shell. 



himarginata. Bimarginate ; having the lip with 

 a double margin. 



