ODONTOSTOMUS. 85 



doubt. As his description is not accompanied by a figure, and 

 probably pertains to an allied but not identical species, I do not 

 think it necessary to reproduce it in this place. 



0. stBSEXDEN/TATUS Doering. 



Shell profoundly rimate, fusiform, ventricose, thick, opaque, 

 chalky-whitish, \vrinkle-striate. Whorls 10, a trifle convex, the 

 first generally whitish-corneous, last whorl about one-third the total 

 length, peristome lipped. Length 23^, diam. 8, aperture with peris- 

 tome 8 mill, long, 4 wide. 



Yar. Large, swollen, usually with a sixth tooth on the right 

 margin. Length 27, diam. 9 mill. 



Argentina: Sierra de Cordova. 



Odontostomus subsexdentatus DOERING, Bol. de la Acad. Nacional 

 Ciencias, Cordoba, 1875, p. 454. Bulimus (Odontostomus) subsex- 

 dentatas KOB., Nachrichtsblatt d. D. Malak. Ges. viii, 1876, p. 6. 

 PFK., Monogr. viii, p. 609. Odontostomus pseudoscxdentatus 

 DOERING, Periodico Zoologioo i, pt. 3, p. 194 (1875). 



Doering, in his second publication of this species, changed the 

 name, without mentioning that previously given. His later diag- 

 nosis is as follows : 



0. pseud osexdentat us. Shell rimate-perforate, ovate-fusiform, 

 ventricose, thick, opaque, calcareous-whitish, wrinkle-striate. Spire 

 attenuate, acuminate. Whorls 10, slightly convex, the first usually 

 whitish-corneous, the rest calcareous whitish ; last whorl about one- 

 third the length, depressed on the side, anteriorly shortly and slightly 

 two-crested at the base. Aperture angularly oblong-oval, obstructed 

 by 5 teeth : one in the middle of the parietal wall, the second, 

 horizontal, on the columella, third on the basal Up, fourth and fifth 

 small, within the right margin. 



Length 23, diam. 7j, length of aperture 7J, width 5 mill. 



Length 23J, diam. 8 to 8J, length of aperture 8, width 5 mill. 



Length 23, diam. 8, length of aperture 7|, width 5 mill. 



The upper tooth of the outer lip is generally but little developed, 

 rarely failing completely. The species varies a good deal in shape, 

 there being two chief forms, a smaller normal one, and a larger, 

 more ventricose form (major) with some traces of a tooth on the 

 upper curve of the outer lip, and measuring : 



Length 26, diam. 9J, length of aperture 8|, width 6 mill. 



