100 DENTALIUM-L^VIDENTALIUM. 



D. translucidum Desh., Mem. Soc. Hist. Nat. Paris, ii, p. 362, pi. 

 16, f. 26 (1825). Not of Sowb., Thes. Conch., iii, p. 98, pi. 225 f. 

 47 (1860). — Not Antalis translucidum Cless., Couch. Cab., p. 24. 



The form identified as translucidum by Sowerby has a linear, very 

 long slit, and belongs to the subgenus Fustiarla Stol. Deshayes 

 states that there is no slit in his D. translucidum (see Monogr. Dent., 

 p. 345) ; so it is evident that Sowerby's shell is a different thing. 



D. AMBiGUUM Chenu. PI. 19, fig. 4. 



Shell somewhat straight, smooth; whitish-gray maculated with 

 black or violaceous, the apex very acute. (Che^iu). 



Locality unhaown. 



D. ambiguum Chenu, Illustr. Conch., i, p. 1, pi. 3, f. 1. 



According to Deshayes' manuscript note, the sole example of this 

 species had long lain dead in the mud, and become blackened in 

 color in place of the pale corneous or yellow which was probably the 

 normal tint. It is allied to D. translucidum, but longer and less 

 arcuate. The surface is smooth and glossy. Length 37, diameter 

 of aperture 3 mill. 



D. CALLTPEPLUM Dall. PI. 19, fig. 9. 



Shell ivory-white to pale salmon color, glistening, elegantly arched* 

 rapidly increasing ; sculpture of faint girdling incremental lines, and 

 toward the tip faint longitudinal scratches, hardly discernible ; sec- 

 tion circular, the lower edge projecting a little in the adult aperture ; 

 tip entire, circular in the youngest, but in the adult with a wide 

 very shallow notch on the concave side. Anterior diameter, 5"0 ; 

 posterior diameter, 0*5; length of shell, 61 '5 ; height of arch above 

 the chord, 10-0 mill. {Dall). 



Near Santa Cruz, in 180 fms. ooze; off Saba Bank, a fragment, in 

 150 fms. ; off Guadelupe, in 175 fms., sand; off Santa Lucia, in 116 

 fms., hard bottom ; off^ Grenada, in 92 fms., sand (Blake). Also off 

 South Carolina, in 159 fms., sand, and in the Gulj' of Mexico, m 169 

 fms., mud (U. S. Fish Commission). Also Pliocene of Caloosahat- 

 chie River, Florida. 



D. eallipeplum Dall, Blake Rep., Bull. M. C. Z., xviii, p. 419, 

 pi. 27, f. 12b. (1889) ; Bull. U. S. Nat. Mus., no. 37, p. 76, pi. 27, f. 

 12b (1889) ; Trans. Wagner Free Institute of Science, iii, p. 442. 



This elegant species has also been received from the coast of Hon- 

 duras and from Samana Bay, St. Domingo. Its nearest relative is 



