WEST AMERICAN PYRAMIDELLID MOLLUSKS. 27 



not apparent in the suture in the first four whorls, but from the 

 fifth on, the summit of the whorl drops more and more anterior to the 

 peripheral sulcus until, on the last whorl, it is about one-fifth of the 

 distance between the whorls posterior to the suture. Base of the last 

 whorl rather prolonged, marked by lines of growth, provided with a 

 strong basal fasciole. Aperture ear-shaped; posterior angle acute; 

 outer lip thin, marked in the following manner within : A white band 

 immediately below the summit, one-fourth of the width of the space 

 between the sutures, followed by an. interrupted band of dark rust 

 brown, succeeded by a broad area, clouded with various shades of 

 rust brown which connect the dark colored band with the white colu- 

 mellar area; columella moderately strong, provided with three 

 oblique folds, the posterior one of which is lamellar; parietal wall 

 covered with a thin callus. 



The specimen described belongs to the Paetel collection, Berlin 

 Museum. It has nine post-nuclear whorls and measures : Length 11.5 

 mm., diameter 4 mm. It was labeled Oheliscus achates Gould, cf. 

 crocatus A. Adams, Japan. In the aperture of the shell a specimen 

 of Anachis diminuta C. B. Adams, was firmly wedged, which species 

 is at home on the west coast of Central America and Mexico. The 

 Pyramidella therefore very likely belongs to the same region. The 

 type of 0. clavulus A. Adams, comes from Acapulco, Mexico. 



It is much narrower with much higher whorls, decidedly less chan- 

 neled periphery and narrower aperture than P. (Pharcidella) achates 

 Gould. 



PYRAMIDELLA (PHARCIDELLA) ACHATES Gould. 



Plate 1, fis. JO. 

 Odostomia achates Gould, Bost. Journ. Nat. Hist., vol. fi, 1852, p. 385, pi.' 14, 



fip:. 1.3. 



Shell stout, shining, milk-white, with irregular, flammulated spots 

 of rust color, which are densest about one-third of the distance 

 between the sutures anterior to the summits, where they form an 

 almost continuous band. (Nuclear whorls decollated.) Post-nuclear 

 whorls weakly rounded, slightly shouldered and faintly crenulated at 

 the summit, marked by lines of growth, which are somewhat variable 

 in strength, the strongest being on the side of the crenulations. 

 Sutures well impressed. Periphery marked by a moderately strong, 

 spiral sulcus. Base rather long, crossed by many lines of growth. 

 Aperture elongate-pyriform, rather compressed laterally; posterior 

 angle acute; outer lip thin; columella short, heavy, bounded by a low, 

 strong basal fasciole, bearing three oblique folds, the posterior one of 

 which is lamellar and situated a little anterior to tlie insertion of the 

 columella; the other two folds are much less strongly developed and 

 more oblique; parietal wall covered with a thin callus. 



