158 BULIMULUS-SONORINA. 



species is readily distinguished from B. inseendens by the internal 

 lamina, which has about the form of that of B. spirifer, though 

 more oblique. It differs conspicuously from B. spirifer in being of 

 a more slender form with smaller aperture, the lip but little ex- 

 panded, surface smooth though without the oily gloss seen in spiri- 

 fer, and with hardly any spiral sculpture or granulation. The apex 

 is like that of B. spirifer. 



Pfeiffer originally described B. rimaius without knowledge of its 

 habitat, and it has later been surmised to be a Central Asian Bui- 

 iminus. Ancey, who had not seen the species, offered the suggestion 

 that it belonged to the South American group of B. derelictus (see 

 Vol. X, p. 172). Reeve's figure of Pfeiffer's type is copied in our 

 tig. 4. Von Martens (Biologia, p. 252) is mistaken in referring 

 B. rimatus to B. spirifer. 



B. SPIRIFER (Gabb). PL 21, figs. 87, 88, 89, 90, 91, 



Shell deeply rimate (the axis perforate above), elongated with 

 oval body-whorl and long conic spire, rather thin ; corneous-brown, 

 nearly uniform or with slightly darker oblique streaks, with a 

 whitish sutural line; very glossy, the surface showing slight growth 

 wrinkles, and under the lens, fine spiral series of long granules 

 caused by decussating spiral striae, variable in development but al- 

 ways rather faint ; two apical whorls finely, vertically costulate, the 

 apex obtuse, with axial dimple passing into a deep suture. Whorls 

 6 to 7, somewhat convex with shallow sutures, the last whorl 

 oval. 



Aperture ovate, fleshy-brown within ; peristome broadly ex- 

 panded, reflexed, sometimes revolute, flesh-tinted ; the terminations 

 approaching, connected by a thick or thin callus. Columellar mar- 

 gin dilated above, the columella passing above into a strong, whitish, 

 spirally entering fold, which within the last whorl becomes a high, 

 callous or laminar crest, revolving about the axis (fig. 89), but not 

 penetrating deeper than the last whorl. 



Alt. 41, diarn. 18 ; alt. of aperture 19 mill. 



Alt. 32, diam, 15 ; alt. of aperture 16? mill. 



Alt. 33?, diam. 15 ; alt. of aperture 16 mill. 



Lower California, from San Antonio, below La Paz, to near San 

 Borja, in the mountains among rocks (Gabb) ; San Jose, on the 

 Gulf of California (Belding) ; near La Paz (Brandegee) ; around 

 the volcano of Las Virgines (Diguet). 



