94 ODONTOSTOMUS. 



c l . Cylindrical, the whorls flattened; corneous-whit- 

 ish ; 26x11 mill. brackebuschi, p. 100. 

 c 2 . Subcylindrical, the cone of spire very short; 

 rufous-brown, a whitish keel above the sutures; 

 whorls flat ; 26x12 to 29x14 mill. 



weyenberghi, p. 100. 



c 3 . Ovate-oblong, more slender than the other spe- 

 cies ; 27x10 mill. multiplicatus, p. 101. 



2. Aperture comparatively open, with three moderate sized and often 

 some smaller teeth ; transverse barrier small or wanting. Bahia 

 Blanca inland to Sierra Ventana. patdyontcns, p. 95. 



O. DENTATUS (Wood). PI. 14, figs. 15, 16, 17 ; pi. 15, fig. 25. 



Shell deeply perforate and rimat^, oblong, of a dirty corneous tint, 

 rather dull, faintly marked with growth -lines. Spire very convexly 

 conic, the apex obtuse. AVhorls about 6^, moderately convex, aper- 

 ture ovate, nearly closed by 8 or 9 teeth : a composite, deeply enter- 

 ing parietal lamella, a very large, spreading and partly vertical colu- 

 mellar lamella, a small, acutely compressed basal fold ; and within 

 the outer lip a similar lower palatal ibid, an accessory fold often be- 

 tween these two ; a large, twisted upper palatal, and a pair of con- 

 tiguous superpalatal folds, connected at their bases ; behind the lower 

 palatal fold a high transverse lamella stands. Peristome white, thick- 

 ened and narrowly reflexed. 



Length 20, diam. 85, length of aperture 8^ mill. 



Length 19, diam. 8, length of aperture 8^ mill. (Montevideo). 



Length 16, diam. 8, length of aperture 7^ mill. (Montevideo). 



Length 16^, diam. 7^, length of aperture 7 mill. (Montevideo). 



Uruguay : Montevideo, in abundance (Martinez, Dr. W. H. Rush); 

 Colonia. Argentina, prov. Entre Rios : Feliciano and San Jose 

 (Orbigny); Concordia and Mercedes, among plants in sandy places 

 (Paz); Gualeyuaychu (L. D. Vries). 



Helix dentata WOOD, Index Testae. Suppl., pi. 8, f. 71 (1828). 

 Bnlimus dentatus Wood, PFR., Symbolaj ad Hist. Hel. iii, p. 54; 

 Monogr. ii, p. 86 ; iii, 369 ; iv, 438 ; vi, 76 ; viii, 107, 612 ; Conchyl. 

 Cab. p. 139, pi. 16, f. 4-6. REEVE, Conch. Icon., pi. 38, f. 233. 

 HIDALGO, Viaje al Pacih'co, Moluscos, p. 80. B. (Odontostomus) 

 dentatus STROHEL, Material! per una Malacostatica di terra e di 

 acqua dolce dell' Argentinia Meridionale, p. 17, exclusive of var. 



