84 ODONTOSTOMUS. 



Argentina : Sierra de Rioja, around the town of the same name 

 (Dr. Stelzner). 



0. riojanus DOER., Bol. Acad. Cienc. Cord., 1875, p. 454. 0. 



riochanus DOER., Periodico Zool. i, pt. 3, p. 190 (1875) Bulimus 



riojanus PFR., Monogr. viii, p. 610. KOBELT, Nachrbl. d. D. 

 Malak. Ges. viii, 1876, p. 6. 



The form is more swollen and the right margin of the peristome 

 is more curved than 0. martensi and 0. pseudosexdentatus. The 

 basal carinae and pits behind the outer lip are but little developed. 



Doering altered the spelling of the name in his second publication 

 of the species, but the change seems unnecessary. 



0. ALVAREZII (Orbigny). 



Shell elongate, pyramidal, distinctly umbilicate, thick, longitu- 

 dinally striate ; spire long, the suture deep. Aperture angular, 

 irregular, showing 5 teeth; two on the columella, three on the outer 

 lip, the upper one [that is, the lower palatal fold] marked outside 

 by a depression. Peristome thin and sharp. Length 19, diam. 6 

 mill. (Orb.). 



Argentina : Province of Entre-rios, at the village Feliciano, on the 

 Parana river (Orb.). 



Helix alvarezii ORB., Mag. de Zool. 1835, p. 22, no. 120. 

 Bulimus alvarezii ORB., Voy., p. 319 PFR., Monogr. ii, 139 

 Odontostomus alvarezii Orb., DOERING, Periodico Zoologico, i, pt. 3, 

 p. 193 (1875). 



It was found dead and bleached in a layer of humus containing 

 fragments of land and river shells, over 60 meters above the present 

 level of the Parana river. d'Orbigny suppcsed that the species had 

 been killed out by the custom the colonists have of burning over the 

 plains to renew the pasturage. It will probably be found to survive 

 in some locality. In the original publication d'Orbigny describes it 

 as with " dentibus septem, duobis supra colurnellam, duobus margi- 

 nata; " some of the teeth being thus unaccounted for ; but as the rest 

 of the description agrees verbally with that in the Voyage, I presume 

 that " septem " was written inadvertently. The species has not been 

 figured and apparently belongs near Q t charpentieri. 



Dr. A. Doering has identified some specimens collected by Dr. 

 Stelzner in the Sierra de Tulumba, in the northern part of the 

 Province of Cordova, with Orbigny's species, but not without some 



