20 BULIMULUS-SCUTALUS. 



sometimes predominating; or chestuut-brown with a few lighter 

 streaks and a basal yellow band. Surface with rather coarse and 

 irregular wrinkles in the direction of growth-lines, decussated by 

 unequally spaced spiral incised striae which cut the wrinkles into 

 granules to a greater or less extent. Spire rather acutely conic, 

 whorls 6 to 6, the earlier densely and minutely wrinkle-pitted, 

 slightly convex, separated by impressed sutures with a crenulated 

 whitish border below. 



Aperture half the shell's length or little more, vertical or slightly 

 oblique, ovate, purple-white or purple inside, with a wide white bor- 

 der within the outer lip ; peristome blunt, a little expanded below ; 

 columellar margin broadly dilated above. 



Alt. 40, diam. 23 ; alt. of aperture 21 mill. 



Alt. 42, diam. 23 ; alt. of aperture 22 mill. 



Bolivian plateau: Palca and Capinata, prov. Cochabamba, and 

 valley of Cochabamba, in gardens ; Viloma (Orbigny) ; and in Pern : 

 from Obrajillo to Diezmo and Oeopa (Angrand). 



Helix thamnoica D'ORB., in Mag. de Zool., 1835, p. 16 ; Amer. 

 Merid., pi. 37, f. 4, 5, 6, 7. Bulimus thamnoicus D'ORB., Voy. 

 Amer. Merid., p. 290 (exclusive of varr. C, D.). PFR., Monogr., 

 ii, p. 185. MORELET, Ser. Conch., iii, p. 174. B. tupacii (in part) 

 REEVE, Conch. Icon., pi. 15, f. 86a, 86c. Bulinus thamnoicus SOWB., 

 Conch. Illustr., pi. 139, f. 70. 



B. tupacii has the spire longer than this species, and the aperture 

 is less than half the length of the shell, while in thamnoicus it is 

 slightly or decidedly more than half the length. B.alauda is more 

 elongated, less roughly striate, and has numerous interrupted spiral 

 bands. B. revinctus is a smaller and much more obese shell, with 

 different apical sculpture. 



D'Orbigny regarded the light colored form, such as that figured 

 on pi. 30, fig. 9, as typical. The intergradation of these with dark 

 forms (pi. 2, fig. 21) is complete. 



B. PLUTO (Crosse). PL 2, figs. 24, 25. 



Shell with partly covered umbilicus, oval-oblong, quite thick, 

 solid, grooved by longitudinal riblets and covered with a thin yel- 

 lowish-fawn cuticle. Color livid fleshy- white with numerous small 

 darker bands of chestnut-brown, of unequal sizes, and some spaced 

 whitish maculations, neither numerous nor conspicuous. Spire conic, 

 the apex rather obtuse. Suture quite irregular, whitish and crenu- 



