loö 



three prominent spiral carlnae, and about 26 (anteriores 

 2 majores) less prominent transverse slender ridges, the 

 intersections being feebly nodulous; anteriorly with an 

 additional slightly nodulous spiral ridge: apex acute: 

 spire with the outlines nearly rectilinear: Avhorls about 

 9, a httle convex, a distinct suture ; last Avhorl terminat- 

 ing very abruptly, concave anteriorly: aperture subor- 

 bicular; canal extremely short very wide." 



„Length of spire O,,, inch; tot. length 0,,5 inch; 

 br. 0,045 inch." 



Cerithium flavum Ad. Contr. p. 122. (1850). 

 Hab. Jamaica (Ad.) St. Thomas (Riise.) 



241. Bittium (Platygyra) gracile Sow. 



„T. alba vel fusca, tenui, parva, attenuata; anfrac- 

 tibus numerosis, obliquis, costis spiralibus et lineis eleva- 

 tis longitudinalibus reticulatis." 



The whorls are obUque numerous and ventricose. 



Cerithium gracile Sow. Thes. p. 287. f. 223. 224. 

 Nr. 137. 



Hab. St. Thomas (Eiise), Loc. ign. (Mus. Metcalf.) 

 * 242. Bittium (Platygyra?) rugulosum C, B. Ad. 



„Sh. conoid, turrited: Avhite: with one slightly ele- 

 vated and three much elevated spiral lines, and on each 

 whorl about 16 to 18 transverse ridges, the intersections 

 being well developed into nodules, anteriorly with a 

 fourth Spiral nodulous slender ridge: apex acute: spire 

 with the outlines nearly rectilinear: whorls about ten, 

 quite convex, with a well impressed suture; last whorl 

 terminating rather abruptly, somewhat concave anteriorly; 

 aperture suborbicular : canal reduced almost to a broad 

 deep notch." 



Lgth. of spire 0,1, inch; tot. length 0,i, inch; 

 br. 0,055 inch." 



Cerithium rugulosum Ad. Contr. p. 121. 



Cerithium rugulosum Ad. Sow. Thes. Nr. 135. 

 f. 237? 



