212 



Cerithium continued. 



thiara. . turreted, rather cylindrical ; whirls crowned with 



tubercles, flat beneath ; the lip alated f inch. 

 mutabile. . three transverse striae on each whirl, the lower whirl 

 with the upper stria tuberculated stronger than the others, 

 upper whirl with the striae all alike 1| inch. 

 semicoronatum. . turreted ; three granular striae on each whirl, 

 the uppermest thickest ; a plait on the columella 1| inch. 

 cinctum. . conical, turreted ; three granular striae, rather equal 



in size ; a plait on the columella If inch. 

 plicatum. . turreted, subcylindrical ; whirls granulated longi- 

 tudinally 1 inch. 



conoideum. . short, conoidal, three or four rows of granulse on 

 each whirl 1^ inch. 



confluens. . turreted, with three transverse granulated keels, the 

 lowest the largest, granulse confluent f inch. 



clavus. . subulate ; two or three transverse granular striae, ver- 

 tically confluent ; base short and twisted f inch. 



baccillum. . subulate, with eight or nine unequal obscure granular 

 striae f inch. 



scabrum. . pyramidate ; echinated with two dentated keels, the 

 lower the largest f inch. 



asperellum. . conical, with two dentated keels, teeth very small 

 var. ? small. 



turritellatum. . turreted ; whirls convex, with three transverse 

 striae, and vertical bowed ribs 1 inch. 



mitra. . conical, with four vertical striee, crossed by small gra- 

 nular ribs small. 



pleurotomoides, . conical, turreted, with two rows of obtuse 

 tubercles ; a notch in the right lip small. 



involutum. . conical, turreted ; turns smooth, imbricating ; colu- 

 mella twisted 1 inch. 



tuberculosum. . turreted ; two rows of tubercles, the upper 

 largest, the lower margins crenulated 1^ inch. 



bicurinatum. . turreted, with subangulated keels ; four trans- 

 verse striae at the base f inch. 



trocMeare. . conical, subturreted ; two transverse keels, raised 

 and dentated, crossed by vertical ribs, giving an alveolated 

 appearance sm all . 



trochiforme. . conical, short ; striae obsolete ; longitudinal ribs 

 very small. 



muricoides. . conical, ventricose ; tubercular and granular striae ; 

 whirls convex | inch. 



purpura. . conical, short ; transversely striated, and distinctly 

 tuberculated var. ? | inch. 



conoidale. . short ; the whirls flat, with unequally truncated 

 and subtubercular striae small. 



subulatum. . turreted, with noduliform ribs and transverse obso- 

 lete striae ; opening oblong. 



lupidorum. . turreted ; whirls convex, subtubercular in the 

 middle ; bowed vertical ribs, nearly obsolete 1| inch. 



