56 DENTALIUM-ANTALIS. 



A few Antillean and Pacific species are grouped here for want of 

 a better place. 



D. DISPARILE d'Orbigny. PI. 14, figs. 16, 17, 18, 19, 20, 21. 



Shell small, solid, moderately curved, opaque white, frequently 

 with some or all of the ribs articulated with dots and dashes of trans- 

 lucent gray. Sculpture, 9 or 10 primary ribs with smooth (or 1- 

 ribbed) interstices at and near the smaller end, increasing by inter- 

 calation to somewhat over double that at the aperture, the interstitial 

 riblets developed earliest and most numerously on the convex side 

 of the shell, where they become as prominent as the primary ribs ; 

 several of the latter, on the concave side of shell, frequently continu- 

 ing prominent to the aperture. Aperture circular, outer margin of 

 peristome crenulated by the riblets. Anal orifice small, without slit 

 or notch, frequently bearing an inner tube (figs. 20, 21). 



Length 20, diam. of aperture 2'3, of apex 1 mill. (St. Martin). 



Length 19*5, diam. of aperture 2*2, of apex 0*7 mill. ] Marco, 



Length 20, diam of aperture 1*9, of apex 0'7 mill, j Florida. 



Length 25, diam. of aperture 3 mill. (Turks I.). 



Coast of Florida, in 2-10 fms. (Hemphill, Rush, Vodges et a/.); 

 Martinique (Orbigny) ; Bahamas (Rawson, Gabb) ; Havana, Cuba 

 (Arango) ; Samana Bay, St. Domingo (Couthouy) ; Barbados, 100 

 fms., (Blake Expedition) ; St. Martin (Marie) ; Miocene and Pliocene 

 of the Carolinas and Florida. 



D. disparile ORB., Moll. Cuba, ii, p. 202, pi. 25, f. 14-17 (1842). 

 -DALL, Bull. M. C. Z., ix, p. 37, 1881 (ex parte) ; Ibid, xviii, 

 Blake Rep., p. 424 (1889) ; Trans. Wagner Inst., iii, p. 440 ; Bull 

 U. S. Nat Mus. no. 37, p. 76. ARANGO, Cont. Faun. Mai. Cub., 

 p. 232 (1878). 



" This species has no notch or slit when perfect ; when truncate it 

 repairs da mages by projecting a small tube from the broken end (figs. 

 20, 21). It recalls D. panormitanum Jeffreys, but is smaller, less uni- 

 form in sculpture, and has no notch. At the posterior end it is cir- 

 cular, with the exterior crenulated by the ribs ; by this feature it is 

 distinguished from some of the allied species whose posterior section 

 is polygonal." (Dall). 



D. disparile has the ribs more unequal than in D. antillarum, and 

 fewer in number at the aperture. Of course the count of ribs at the 

 apex depends upon the age of the individual specimen, the secondary 

 riblets being added very early on the convex side. 



