DENTALIUM-FISSIDENTALIUM. 75 



slit at the apex is longer than in D. capillosum, in which, moreover, 

 the sculpture is obsolete toward the aperture. The same author 

 recognizes a var. major attaining the length of 113 mill. We have 

 seen some hundreds of specimens of D. candidum and a number of 

 D. capiilosum, none with so long a slit as is indicated for the D. 

 ergasticum, specimens of which we have not seen. Pending full 

 comparisons of Fischer's shell with the earlier described forms, it 

 may be best to let it stand as a species, although the mere length of 

 the slit is generally a variable character and of correspondingly 

 minor importance. Fischer's original diagnosis does not agree fully 

 with Locard's remarks. The figure of our plate, copied from Lo- 

 card, evidently belongs to his var. major, though this is not stated in 

 his text. It shows an elliptical section, while ergasticum has the 

 aperture " exacte circularise Compare D. capillosum var. pauti- 

 costatum. 



D. MILNEEDWARDSI Locard. 



Shell of large size, of conoid, very elongate form, stout, arcuate 

 above; base exactly circular, quite oblique, the tube adjacent to it 

 nearly cylindrical and straight as far as the middle, then tapering 

 and arcuate, the greater part of the concavity in the upper three- 

 fourths of the total length. Summit quite thick, very rapidly tap- 

 ering ; apical slit small, rather wide. Shell very thick, very solid, 

 ornamented throughout its length with quite strong, quite regular, 

 flat, compressed longitudinal ribs, separated by simple striae which 

 are narrow but deep. Growth-striae sloping, weak, a little more 

 marked toward the base. Coloration a nearly lusterlegs light red. 

 Length 82, greatest diam. 12, curvature 3 mill. (Locard). 



West coast of Africa, off the Soudan, in 1435 meters. 



D. milne-edwardsi LOCARD, L'Echange, Revue Linneenne, No. 

 146, Feb., 1897, p. 10. 



D. SEMIVESTITUM " Fischer " Locard. 



Shell very large, of slender form, very narrowly conoid, very at- 

 tenuated, subcyliudrical for the first two-fifths from the base, thence 

 slowly tapering to the apex ; nearly straight or very feebly arcuate 

 in the cylindrical part, with a stronger curvature along the latter 

 moiety of the length, summit slowly and progressively tapering. 

 Base obliquely truncate and almost exactly circular; apical slit 

 extremely short, formed simply by a notch. Shell somewhat thin, 

 solid, a little glossy, ornamented nearly the entire length by very 



