1 52 BULIMULUS-BOSTR YX-PERON^EUS. 



Aperture oblong-oval; peristome simple, acute, straight; col- 

 umellar margin reflexed, half covering the perforation. Alt. 17-19, 

 diam. 6$-7 mill.; aperture, length 6, width 82 mill. (Doer.}. 

 Sierra de Belen, prov. Catamarca, Argentina (Dr. Hieronymus). 



Peronceus calchaquimis DOER., Bol. Acad. Nac. Cien. Rep. Ar- 

 gent., iii, p. 64 (1879). 



Readily distinguished from famcttinus by the color and size; the 

 aperture is relatively smaller, columellar margin a little more nar- 

 rowly reflexed, whorls more convex, etc. 



B. FAMATINUS Doering. 



Shell rimate, thin, fusiform-turrited, longitudinally rather closely 

 costulate, opaque whitish (or rarely with a few corneous streaks) ; 

 spire long, the apex a little attenuated, slightly obtuse. Whorls 7, 

 the earlier yellowish, smooth ; last whorl slightly exceeding one- 

 third the length. Columella simple; aperture oblong, oval ; per- 

 istome simple, straight; columellar margin narrowly reflexed, partly 

 closing the perforation. Length 19, diam. 6 mill.; length of apert- 

 ture 6-65, width 4 mill. (Do&ring). 



Sierra de la Rioja, at about 2000 meters alt., betiveen Rioja and 

 Ckilecito, Prov. Rioja, Argentina (Stelzner). 



Peronceus famatinus DOER., Bol. Acad. Nac. Cien. Rep. Argent., 

 iii, p. 63. 



The jaw has 12 narrow plaits. Teeth in straight transverse series. 

 It is thus a true Bulimulii*. 



Group of r hod acme. 



B. RHODACME Pfeiffer. PI. 46, fig. 54. 



Shell openly rimate, narrowly long-ovate, rather solid. Wliitr, 

 with irregular pellucid or pink mani/ation, often suffused irit/i >*<- 

 ate blush on the spire, sometime* unicnlorcd white. Surface lusterless, 

 with rude, irregular growth-stride, sparsely decussated, or bearing gran- 

 ule* in spiral series. Spire conic, with slightly convex outlines, the 

 apex obtuse. Whorls 6, the IIJIJHT ones very conir.c with deep sutures, 

 the lower two less convex, suture slightly and irregularly crenulate ; 

 the apical li whorls smooth, corneous or roseate. Last whorl not 

 compressed below. 



