00 ODONTOSTOMUS. 



Length 27, diam. 10, length of aperture 9, width 5 mill. 



Length 27, diam. 9, length of aperture 8, width 6 mill. 



The normal form is more frequent on calcareous hills around the 

 valley of the Rio Primero. on the western slope of the Sierra de 

 Cordova. The var. major predominates in the north of the 

 Province, where Dr. Stelzner collected it at San Pedro. 



O. KOBELTIANUS (* Doering ' Kobelt). PI. 12, figs. 80, 81. 



Shell rimate, fusiform, rather thin, smooth, streaked with alter- 

 nate corneous and opaque whitish, the apex regularly attenuated, 

 generally decollate. Whorls 910, a trifle convex, regularly in- 

 creasing, the last subcompressed at the base, forming a rather wide 

 crest, a narrow deep pit above it. Aperture slightly oblique, angu- 

 late-ovate, with five folds arranged as in 0. chancaninus, except that 

 the uppermost on the outer lip is almost obsolete, while the middle 

 one is deeply placed and shows through as a yellow spot outside. 

 Peristome white, narrowly expanded, narrowly white-lipped within, 

 the margins joined by a thread-like parietal callus, stronger at the 

 ends, nearly interrupted in the middle. Length 27, diam. 7, length 

 of aperture 8, width 5J mill. (Kob.} Argentine Republic. 



Bulimus kobeltianus Doering in litt., KOBELT, Jalirb. d. D. Malak. 

 Ges. 1880, p. 291, pi. 9, f. 15, 16. ' 



O. CHANCANINUS Doering. PI. 12, figs. 78, 79. 



Shell rimate, fusiform, ventricose, opaque, buff, calcareous, closely 

 wrinkle-striate. the apex attenuated, frequently decollate. Whorls 

 9-10, a trifle convex, the first slightly substriate, those following 

 coarsely and closely striate, the last whorl about one-fourth to one- 

 third the total length, depressed in front, the base crested (second 

 crest obsolete). Aperture angularly oblong oval ; obstructed by 5 

 teeth : the first one high, slightly entering, on the parietal wall ; an- 

 other, larger and somewhat twisted, deeply entering on the colu- 

 mella; the other three within the outer lip, the upper one being 

 small and tooth-like; peristome expanded, a little reflexed, thickened 

 within, the right margin subarcuate above, basal and columellar 

 margins a little reflexed, the margins joined by a callus. Length 

 27, diam. 8 mill., aperture with peristome 8^ mill, long, 5J wide 

 (Doer.). 



Argentina ; Western slope of the Sierra de Aconjigasta, under 

 rotten logs in the thorny woods. 



