WEST AMERICAN PYRAMIDELLTD MOLLUSKS. 25 



ODOSTOMIA SUBSULCATA Carpenter. 



Odostomia subsulcata Carpenter, Cat. Mazatlan Shells, 1857, p. 411. 



The two cotypes on tablet 1 955 in the British Museum show one 

 strong and two weak basal folds on the columella. They are young 

 badly worn specimens of some species of Longchseus. 



ODOSTOMIA VALLATA Carpenter. 

 Odostomia vallafa Carpenter, Cat. Mazatlan Shells, 1857, pp. 411-412. 



Tablet 1956 of the British Museum collection contains the three 

 cotypes which like the above must be placed under Longchfsvs for 

 the same reason. 



Subgenus PHARCIDELLA Ball. 



Pharddella Dall, Bull. Mus. Comp. Zool., vol. 18, 1889, p. 233. 



Shell of many whorls, turriculate, faintly spirally striate, not 

 umbihcate; wdth faintly vertically ribbed sulcate periphery, surface 

 of the whorls weakly ribbed ; columellar folds three ; outer lip usually 

 provided with internal lirations. 



Type. — PharcideJla folimi Dall. 



KEY TO THE SPECIES OF THE SUBGENUS PHARCIDELLA. 



Shell broadly conic, stout, large hastata, p. 25. 



Shell narrowly conic, slender, small panamensis, p. 26. 



Shell elongate-ovate. 



Aperture auricular moffati, p. 26. 



Aperture not auricular achates, p. 27 . 



PYRAMIDELLA (PHARCIDELLA) HASTATA A. Adams. 



Plate 1, fig. 4. 

 Oheliscus hastatus A. Adams, Sowerby Thes. Conch., 1854, p. 811, pi. 171, fig. 24. 



Shell broadly elongate, conic, pale yellowish to flesh-color, irreg- 

 ularly clouded with light brown, shining. (Nuclear whorls decol- 

 lated.) Post-nuclear whorls flattened, decidedly crenulated at their 

 summits, with faint grooves extending from the base of the crenula- 

 tions down and across the whorls giving them the appearance of being 

 obsoletely ribbed. Sutures deep and channeled. Periphery of the 

 last whorl angular, deeply sulcate, sulcus more or less regularly 

 closely transversely ribbed. Base well rounded, axially striated, the 

 striae extending to the umbilical region and over the posterior colu- 

 mellar fold. Basal fasciole present. Entire surface covered with 

 microscopic spiral striations. Aperture suboval, subchanneled at the 

 junction of the outer lip and columella, posterior angle acute. Colu- 

 mella straight and strong, posterior fold very strong, lamellar slightly 

 oblique; anterior two of about equal size and much more oblique than 

 the posterior one. Inner surface of the outer lip provided at intervals 

 with five lirations, two posterior and three anterior to the peripheral 

 sulcus. 



