36 DENTALIUM. 



[=20, 3'75 mill.]. The color of this shell is variable, being either 

 milk-white, yellowish or reddish ; the angles are less acute at the 

 larger end ; and at the smaller end there is sometimes formed a tu- 

 bular appendage. (6r. B. $.). 



Xipixapi, West coast of Colombia (Cuming) ; Realejo, west coast 

 of Nicaragua (Dr. A. S. Oersted). 



D. quadrangulare G. B. SOWERBY, Proc. Zool. Soc. Lond., 1832, 

 p. 29. SOWB. JR., Thes. Conch., iii, p. 103, pi. 224, f. 31 ; and in 

 Conch. Icon., pi. 5, f. 27. MORCH, Malak. Blatter, vii, p. 176 

 (1861). 



White, small, striated, cylindrical, four-sided at the apical end, 

 rounded at the other (Sowb.~). The single specimen collected by Dr. 

 Oersted measures, length 6?, diam. H mill. 



D. FISHERI Stearns, n. sp. PI. 5, figs. 61, 62, 63, 64, 65. 



Shell cylindrical becoming square toward the apex, not much taper- 

 ing, and nearly as wide at apex as at aperture ; moderately arcuate ; 

 comparatively solid and strong. White with the riblets gray ; luster- 

 less. Sculpture of four strong angles at and near the apex, where it is 

 square; these angles rapidly decreasing in prominence until at the 

 first third of the shell's length the section is almost round. Very 

 near the apex each of the four faces is parted by a median riblet ; 

 and a little further on a tertiary series of riblets, one in each of the 

 intervals except the two bounding the keel of the convex side, in 

 which intervals small riblets develop later. At the middle of the 

 shell's length the section is circular and the 28 to 30 riblets nearly 

 equal in size ; a few threads are intercalated toward the aperture, 

 where the riblets are slightly unequal, low, narrow and close. Aper- 

 ture circular, slightly oblique. Anal orifice circular, with a slightly 

 raised rim ; placed in the middle of the square apex. Length 14*1, 

 diam. at aperture 1*8, at apex 1*2 mill. 



Los Animas Bay, Lower California (type no. 46204, U. S. Nat. 

 Mus.). 



D. fisheri STEARNS, Proc. U. S. Nat. Mus., xvii, 1894, p. 157 

 ("provisional" name only; no description). 



This species is evidently near to D. quadrangulare Sowb. of Col- 

 ombia, but it is narrower in proportion to its breadth. We have not, 

 however, been able to compare specimens of Sowerby's species. The 

 general system of sculpture is the same as in several allied species ; 



