1G6 



PROCEEDINGS OF THE ACADEMY OF 



[Feb., 



Length 254 mm. (posterior end broken) ; greatest diam. 3.7 mm. 

 Pliocene(?), Costa Rica, William M. Gabb. 



This species was referred to the European D. dentalis by Gabb, but 

 it is not closely allied to that species. 



Dentalium (Tesseracme) dissimile Guppy. 



Proc. Acad. Nat, Sci„ 1897, p. 469, pi. XI, figs. 3-5 (January 18, 189S). 



A common form in the Bowden bed, and the largest Jamaican 

 species. 



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Figs. 1, 2. 

 Dentalium macilentum. 



Fig. 3. 

 D. costancense. 



Fig. 4. 

 Cadulus simrotlu. 



Dentalium (Episiphon) macilentum n. sp. Figs, l, 2. 



Shell small, moderately curved, excessively slender, slightly tapering; 

 surface smooth, somewhat glossy, with slight growth-lines only. Tube 

 very strongly compressed laterally throughout, wider and thicker along 

 the concave than the convex side. Both apertures oval or oblong. 

 Young stage acicular. 



Dimensions of largest (though imperfect) specimen: Length 8.8, 

 antero-posterior diameter at aperture 9.1, at apex 0.7 mm.; lateral 

 diameter at aperture 0.7, at apex 0.6 mm. 



Bowden bed. 



An abundant form, very strongly compressed laterally, sometimes 



