DENTALIUM-L^SVIDENTALIUM. 105 



D. caudani LOG., Ann. Soc. Agric. Lyon (7), iv, p. 213 (1896) ; 

 Res. Sci. Camp, du Caudan, i. p. 171, pi. 6, f. 2. 



Particularly characterized by the great size and the smooth, 

 glossy shell. It is much less slender than D. perlongwn Dall, 

 straighter below, and oval in section. 



D. MATARA Dall. PI. 18, figs. 14, 15, 16, 17, 18. 



Shell slender, salmon-colored, whiter toward the aperture, glisten- 

 ing, the lines of growth hardly perceptible in fresh specimens, other 

 sculpture none ; very slightly arched ; aperture circular, very little 

 oblique ; anal orifice higher than wide, slightly notched below and 

 above, with a short, wide notch, but on the convex side this is pro- 

 longed by a rather wide slit, about TO mill. long. Length of shell 

 41 , diameter of aperture 2*75, of apex 0*6 mill. ; height of arch above 

 the chord 3'75 mill. (Dall). 



Of Cape Lookout, N. C., in 22-31 fms., sand ; of Hatteras, sta- 

 tion 2276, in 16 fms. ; and in the Gulf of Mexico, in 26 and 111 fms., 

 sand and mud (U. S. Fish Commission), also at Samana Bay, Santo 

 Domingo in 16 fms., mud (Couthouy, in 1854). 



D. matara DALL, Blake Rep., Bull. M. C. Z., xviii, p. 420 (1889) ; 

 Bull. U. S. Nat. Mus., No. 37, p. 76. 



Belongs to the same group as perlongum ; there are no striae 

 near the apex as in D. leptum, which, moreover, is smaller and less 

 colored. The apex has an unusually high "sheath " (figs. 16, 17, 

 18) in typical specimens, but in some there is only a very short one 

 (figs. 14, 15). The color varies from a flesh tint to carnelian. Dall 

 writes as follows: 



This shell is colored like D. rubescens, but has a shorter and very 

 different notch ; is slimmer, straighter, and has a proportionally 

 larger posterior end when perfect. It is less conical, less arched, 

 and smaller than D. callipeplum, which it resembles in brilliancy. 

 It entirely wants the fine posterior striation of D. leptum Bush, 

 which is still more slender (Dall). 



D. RUBESCENS Deshayes. PI. 19, fig. 2. 



Shell slender, moderately arcuate, but the bend mainly in the 

 smaller third of the length, rather thin. Carnelian tinted, paler 

 toward the aperture. Surface smooth and glossy, with no longitudi- 

 nal sculpture and only faintly-indicated growth-lines. Aperture 

 circular, the peristome thin and acute ; anal orifice circular with 

 thin margins, and on the convex side a short slit (or according to 



