BULLETIN OF THE UNITED STATES FISH COMMISSION. 
456 
Dentalium disparile d’Orbignv. 
Dentalium disparile d'Orbigny, Moll. Ctibana, it, p. 202, pi. xxv, figs. 1 4-17, 1845. 
Shell small, solid, somewhat curved, opaque white, the ribs often blotched with gray, with nine or 
ten primary ribs, often with intermediate ribs at the smaller end; aperture circular, showing the 
riblets on its border; anal orifice small, entire. 
Length, 20; diameter, 2 mm. 
A fragment of the posterior end of a shell was obtained at Mayaguez, Porto Rico. 
Dentalium ceratum Dali. 
Dentalium ceralum Dali, Bull. Mus. Comp. Zool., ix, p. 38, 1881. 
Dentalium ceratum Dali, Blake Report, it, p. 424, pi. xxvi, fig. 5, 1889. 
Shell moderately curved, the anterior part smooth and shining, milky white; posterior part dull 
greenish ; there are from seven to ten well-developed ribs at the posterior end, and there are intermediate 
riblets farther up the shell; all the ribs fade out on the upper third; apertures simple. 
Length, 30; diameter, 5 mm. 
Two line shells were obtained at Mayaguez Harbor, Porto Rico. 
Dentalium antillarum d’Orbigny. 
Dentalium antillarum d’Orbigny, Moll. Cubana, ii, p. 202, pi. xxv, figs. 10-13, 1845. 
Shell small, solid, and stout; last third more strongly curved than the remainder; white or 
greenish yellow; ribs numerous, subequal or alternately larger and smaller, low, rounded; aperture 
circular. The ribs are often marked with gray. 
Length, 23; diameter, 2.5 mm. 
Mayaguez, Porto Rico, two dead shells. 
Subgenus Ltevidentalium Cossmann, 1888. 
Dentalium callipeplum Dali. 
Dentalium callipeplum Dali, Blake Report, ii, p. 419, pi. xxvn, fig. 125, 1889. 
Shell ivory white or flesh color, polished, evenly curved, rapidly increasing; sculpture of faint, 
scattered, incremental lines; apertures round; in the adult that of the posterior end has a wide, shallow 
notch on the concave side. 
Length, 61; diameter, 5 mm. 
Mayaguez, Porto Rico, two young, worn shells and one beautiful specimen two-thirds grown. 
Dentalium matara 'Dali. 
Dentalium matara Dali, Blake Report, ir, p. 420, 1889. 
Dentalium matara Pilsbry & Sharp, Man., xvii,8, p. 105, pi. xviii, figs. 14-18, 1897. 
Shell slender, moderately and evenly curved, polished, salmon or flesh colored, becoming lighter 
anteriorly, with very faint lines of growth; aperture circular; anal opening notched on the concave 
and convex sides, the latter notch is carried up the tube as a slit. 
Length, 40; diameter, 2.75 mm. 
San Juan; Mayaguez, Porto Rico, a few specimens in an immature state. 
Subgenus Episiphon Pilsbry & Sharp, 1897. 
Dentalium filum Sowerbv. 
Dentalium filum Sowerby, Thes. Conch., in, p. 89, pi. ccxxv, fig. 45, 1800. 
Shell delicate, slender, white, moderately curved, nearly transparent, glossy, sculptured with 
very fine microscopic concentric lines which are seen most plainly at the posterior end; aperture 
circular, the margin more or less irregular; posterior end truncated, with an internal pipe, slightly 
notched. 
Length, 12.5; diameter, 1.25 mm. 
Mayaguez, Porto Rico, two worn shells. 
