ABT.18 SMALL SHELLS DREDGED BY '' ALBATROSS " — DALL 127 



CALLIOSTOMA (EUTROCHUS?) TITTARIUM, new species 



Shell small, bluntly conical, white, with about five whorls and a 

 small subglobular nucleus; surface polished, the whorls flattened, the 

 last whorl subcarinate, the base slightly convex, with a minutely perfo- 

 rate umbilicus partly obscured by a reflection of the pillar hp; spiral 

 sculpture variable; usually there is a sharp groove just behind the 

 rather obscure suture, the rest of the of whorl behind this groove 

 smooth; other specimens have several grooves on this part of the 

 shell and others on the base; there are always one or two strong cords 

 around the umbilicus; there is no visible axial sculpture; aperture 

 subquadrate, the pillar lip straight, simple, thickened near its inser- 

 tion. Height, 3.5 mm.; major diameter, 2.5 mm. U. S. Nat. Mus. 

 Cat. No. 108417. 



Off Georgia, three, and off Fernandina, six specimens, mostly in 

 poor condition. 



CALLIOSTOMA HALIBRECTUM, new species 



Shell small, depressed, turbinate, whitish, with about five moder- 

 ately convex whorls, more or less constricted in the sutural region, 

 and a very minute, mostly immersed, smooth nucleus; base flattish 

 and apparently smooth within the rounded peripheral carina; spiral 

 sculpture of (on the last whorl about a dozen) subequal flattish 

 threads between the carina and the preceding suture; these are cut 

 very obliquely by sharp retractive grooves, producing a rather uni- 

 form series of small diamond-shaped, flattish sections of the threads; 

 base imperforate, aperture defective but apparently subquadrate, 

 with a thick piUar. Height of specimen, 6 mm.; major diameter, 

 9 mm. U. S. Nat. Mus. Cat. No. 108126. 



One specimen off Fernandina, in poor but recognizable condition. 



CALLIOSTOMA ARESTUM, new species 



Shell small, brownish or whitish, with four and one-half whorls 

 following a polished white nucleus of somewhat less than one whorl; 

 form subconic with very prominent sculpture; spiral sculpture on 

 second whorl two, on the third whorl three, on the last whorl above 

 the base four, and on the base six spirals, of which two near the 

 periphery are stronger, the one in front smaller but conspicuously 

 beaded, those on the imperforate base similar, smaller, with subequal 

 interspaces, two or three near the axis more prominently beaded; all 

 the spirals show more or less obscure tendency to beading; there is 

 also a fine simple undulated thread between the first two spirals on 

 the last whorl ; axial sculpture only of retractively oblique incremental 

 lines; aperture rounded except as modified by the sculpture, the 

 pillar straight with a conspicuous notch at the anterior end. Height 

 of shell, 5 mm.; of last whorl, 3 mm.; major diameter, 5 mm. U. S. 

 Nat. Mus. Cat. No. 108412. 



