OimXTOSTOMUS. 67 



Argentina: near Cordova (Dr. Stelzner); western slope of the 

 Sierra de Aconjigasta, in moist places, la Mermda, de Jatan, del 

 Nieve, and further south around the Aqua de los Oscuros, under 

 rotten logs in tlie thorny thickets (Doering). 



Bitlinius cordorcutus PFK., Malak. Blatt., ii, 1855, p. 1 l! ; I'. X. 

 S., 1856, p. 34; Novit. Conch., i, p. 70, pi. '20, f. 1, 2; Monogr., iv, 

 435 ; vi, 75 ; viii. 105. DOHRN, Malak. Blatt., xx\], p. 202 (1874), 

 with synonym Scalarinella stehneri Doering; article reprinted in 

 Mai. Bl., xxiv, 1877, p. 157. Cf. KOBELT, Jahrb. d. D. Malak. 

 Ges., v, 1878, p. 150, and v. MARTENS, Biol. Centr. Amer., 

 Moll., p. 251 Macrodontes cordorawts and var. stehneri DOERIM;, 

 Periodico Zool., ii, p. 250 (1877). Otessinia stehneri DOEI:., 

 Periodico Zoologico, i, pt. 3, p. 201 (1875). 



I have not seen this species. 



Var. stehneri Doering. Shell smaller, the whorls more convex, 

 stria; finer, the aperture, sulirotund. Length 16-18, width 4^, aper- 

 ture with peristome 4^ mill, long, 3^ wide (Doer.) 



Sierra de Aconjigasta at Yntan (Serrazuela; Province of Cordova). 



Subgenus SPIXIA Pilsbry and Vanatta, 1898. 



Spixia P. & V., Nautilus xii, p. 57 (September, 1898), type 0. 

 spixii Orb. 



Shell usually turreted with a long spire, the initial two whorls 

 vertically costulute. Aperture obstructed by five teeth: a compressed 

 parietal lamella, an oblique but usually not contorted columellar 

 lamella, compressed upper and lower palatal folds, the latter basal in 

 position, and a small suprapalatal. Of these the suprapalatal and 

 lower palatal may be obsolete or wanting. 



This is chiefly an Argentine group, but a few species extend into 

 southern Brazil. I include 0. neglectus and lemoinei with hesita- 

 tion ; the former has spiral stria; between the vertical riblets on the 

 apex, and forms a transition to the group of 0. janeirensis. In one 

 species provisionally grouped here, the teeth are wanting (p. 91). 



Group of 0. spixi. 



Rather large, solid, turreted species, chiefly of Bolivia, Brazil, and 

 northern Argentina. 



O. SPIXI (Orbigny). PI. 12, figs. 60-63. 



Shell narrowly umbilicate, turreted, brown or corneous-gray with 



