BULIMULUS-ORTHOTOMIUM. 139 



the body whorl is more conspicuous and regular than in the larger 

 species. I have seen no specimens of pilula which appear to be 

 genuine except the types. All the others when critically studied 

 resolve themselves into varieties of sufflatus. 



B. COOPERI Ball. PI. 18, figs. 34, 35, 36, 37. 



Shell umbilicate, globose, inflated, thin ; longitudinally obsoletely 

 wrinkle-striate ; whitish-calcareous with two chestnut bands ; spire 

 short, apex obtuse ; suture impressed. Whorls 4, convex, the em- 

 bryonic 1J [delicately costulate], the last inflated, longer than the 

 spire (in the proportion of 7 to 4). Aperture somewhat oblique, 

 ovate-rounded, white inside ; peristome simple, whitish, the termi- 

 nations separated, columellar margin broadly dilated, reflexed, 

 partly covering the umbilicus; basal and outer margins acute. Alt. 

 11, greatest diam. 8, alt. of aperture 7 mill. (Crosse & Fischer'). 



Lower California: San Jose del Cabo (Bryant). 



Mormus pilula TRYON, Amer. Jourii. Conch., iii, p. 173, pi. 14, f. 

 7. Bulimulas pilula CROSSE & FISCHER, Moll. Terr. Mex., i, p. 

 570, pi. 21, f. 6, 6a. COOPER, Proc. Cal. Acad. Sci. 2d ser., iii, p. 

 102, 210; iv, p. 143, pi. 5, fig. 12, 1894. Not Bulimus pilula 

 Binney as restricted by Dall. Bulimulus cooperi DALL, Proc. U. 

 S. Nat. Mus., 1895, p. 5. COOPER, Proc. Cal. Acad., v, p. 163. 

 Bulimulus (Orthotomiwn) cooperi DALL, Proc. U. S. Nat. Mus., 

 xix, p. 358. 



" This form, distinguished among other things by pale peripheral 

 banding, is quite distinct from the true B. pilula of which the types 

 are in the National Museum." (Dall). 



The longitudinal wrinkling is quite distinct, but there are no 

 spiral lines or granulation. 



B. DECIPIENS Cooper. 



"I propose this name for a new form, of which three specimens 

 were brought from San Lazaro Mt. They were living but appar- 

 ently quite young, too immature to figure. The largest is nearly of 

 the size and form of B. pilula as figured, but still more globular, 

 being shorter and wider, with three whorls. It is more Heliciform, 

 much resembling H. calif or niensis, young, and like that has a single 

 vittiform band around the periphery, which becomes hidden in the 

 suture of two upper whorls. The band is however, paler than the 

 brownish epidermis (faded in alcohol). To prove their affinity to 



