162 BULIMULUS-SONORINA. 



acute, shining, narrowly perforate; whorls 6, the first convex, pe- 

 nultimate much more convex, separated by an impressed suture, the 

 last whorl large, nearly two-fifths the entire alt., a little ascending in 

 front. Aperture oblong-ovate, acute above, narrowed below ; peri- 

 stome sub-continuous, broadly expanded, slightly thickened, the 

 margins connected by a rather thick callous, outer margin regularly 

 curved, rather broadly reflexed ; columellar margin dilated, patu- 

 lous, nearly concealing the perforation, joining the basal margin in 

 an obtuse angle; columella twisted, having a deeply entering, median 

 laminiferous tooth. Alt. 24, diam. 9 mill.; aperture with peristome 

 11 mill, long, 8 wide (Mabille). 



Volcanic Island of La Tortuga, in the middle of the Gulf of Cali- 

 fornia (Diguet). 



Bulimulus (Leptobyrsus) dentifer MABILLE, Bull. Soc. Philomath. 

 (8) vii, p. 67, 1895. 

 B. DISMENICUS Mabille. 



Shell ovate-elongate, narrowly rimate, rather thick, solid, some- 

 what opaque, covered with a corneous-rufescent epidermis, a little 

 shining, striatulate ; apex rather obtuse, whitish ; spire conoidal ; 

 whorls 6, little convex, the first slowly, the rest rapidly increasing, 

 separated by a narrowly margined white suture ; the last whorl 

 large, ovate oblong, a little inflated, over half the alt. of shell, de- 

 scending, in front. Aperture vertical, ovate, narrowed above, di- 

 lated below ; peristome slightly thickened, a little reflexed, shining, 

 the outer margin bent in a long arch, basal margin somewhat patu- 

 lous, columellar margin dilated, covering the perforation ; margins 

 joined by a moderately conspicuous glossy callous. Alt. 32, greatest 

 diam. 12 mill. ; aperture with peristome 15 mill, long, 10 wide 

 (Mabille). 



Sierra de la Puna, Lower California, at 1,800 meters elevation 

 (Diguet). 



Bulimulus (Leptobyrsus) dismenicus MABILLE, Bull. Soc. Philo- 

 math. (8), vii, p. 67. 



B. SUBSPIRIFER Mabille. 



Shell narrowly subperforate, elongate, a little thickened, destitute 

 of cuticle, longitudinally striated ; strise dense, filiform, irregular; 

 apex subacute, subperforate ; whorls 8, a little convex, the earliest 

 beautifully costulate, angulate at the suture, the last whorl large, 

 inflated, not descending at the aperture. Aperture ovate-elongate, 



