96 DENTALIUM-GRAPTACME. 



Smith reports D. inversum from Whydah, West Africa (Capt. 

 Knocker !). 



D. SPLENDIDUM Sowerby. PI. 15, fig. 38. 



Shell thin, polished, flesh-colored at base, milk-white toward the 

 apex ; posterior orifice with two slits, one dorsal, the other ventral. 

 Length 1*8, diam. 0'15 inch.=45, 3'75 mill. (G. B. &). 



Xipixapi, west coast of Colombia, 10-16 fms. (Cum ing). 



D. splendidum G. B. SOWERBY, P. Z. 8., 1832, p. 29. SOWB. Jr. 

 Thes. Conch., iii, p. 98, pi. 225, f. 41 ; Conch. Icon., xviii, pi. 5, f. 

 30.? D.fissura Lam., SOWB., Thes. Conch., iii, p. 98, pi. 225, f. 43, 

 not D. fissura of Lamarck, Philippi or Costa. 



The apical slit is somewhat as in D. sectum Desh., but not reduced 

 to a narrow cut above by an apical plug. " Generally reddish near 

 the apex, and white toward the base. In some specimens there are 

 two fissures, one dorsal, the other ventral." 



GROUP OF D. SECTUM. 



Shell subcylindrical, the apex obliquely truncate, with an oblique, 

 convex plug, perforated by a narrow antero-posterior slit. 

 I. Shell longitudinally striated from apex to or nearly to aperture, 



calamus. 

 II. Apical half striated, the rest smooth, sectum. 



D. SECTUM Deshayes. PI. 17, figs. 60, 61, 62, 63. 



Shell small, slender, very little tapering, slightly curved, white and 

 glossy. Sculpture of very numerous, close, subequal fine riblets ex- 

 tending longitudinally from apex about halfway to aperture ; the re- 

 maining half with fine growth-strict, but no longitudinal sculpture. 

 Aperture circular, not oblique, with acute peristome. Apex with a 

 high, obliquely conical, smooth plug , perforated by an antero-posterior 

 slit. Length 24, diam. of aperture T7, diam. of apex below plug 

 1-2 mill. 



Gulf of California (W. Newcomb, in coll. Acad.) ; Habitat un- 

 known (Desh., Sowb.). 



D. sectum DESH., Mem. Soc. Hist. Nat. Paris, ii, p. 367, pi. 18, f. 

 12-14 (1825). SOWERBY, Thes. Conch., iii, p. 99, pi. 224, f. 35 

 (1860) ; and in Couch. Icon., xviii, pi. 5,f. 28 (1872). Antalissecta 

 CLESSIN, Conch. Cab., p. 26. D. diffusum CHENU, 111. Conch., i, p. 

 3, pi. 6, f. 11,12. 



