138 BULIMULUS-BOSTRYX-PERON^EUS. 



B. I'n-iiciifitin MOREL., Journ. de Conch., 1860, p. 376 ; Ser, 

 Conch., iii, p. 211, pi. 11, fig. 11. PFR., Monogr., vi, p. 95. Bitli- 

 iii nf n.s (Peron.ceus) verucnlnm PFR.-CLESS., Nomencl. Hel. Viv., p, 

 255. 



Resembles Cylindrella pruinosa of the Isle of Pines, in form, size 

 and coloration. The earlier 8 to 9 whorls form the tapering sum- 

 mit ; the following are nearly equal and their form is quite exactly 

 cylindrical ; the last whorl is angular below. The shell is shining 

 and corneous, appearing smooth to the naked eye, but with magni- 

 fication some growth-stride become visible. The coloration gener- 

 ally consists of a wide russet-brown band revolving upon a whitish 

 ground ; the first whorls are always of a uniform brownish shade. 

 Sometimes the band is indistinct or replaced in whole or in part by 

 oblique streaks, somewhat confused, reaching from suture to suture. 

 (Morel.'). 



Section 7. Perouceus Albers, 1850. 



Peronceus ALB., Die Hel., p. 163. ALB.-MART., Die Hel., I860, 

 p. 221, (type B. pupiformis). PFR.-CLESS., Nomencl. Hel. Viv., p. 

 225. 



Shell rimate or perforate, long and narrow, with 7-11 whorls; 

 aperture ovate, the outer lip expanded or not, columellar lip dilated. 

 Type B. pupiformis Brod. 



The numerous species of this group are restricted to northern 

 Chili, Peru and the adjacent districts of Bolivia. They inhabit rain- 

 less situations for the most part, and are found under or among 

 stones, or at the roots of grass or cacti. Hypsometrically, they 

 range from near sea-level in Chili, to over 13,000 feet altitude on 

 the Andean Plateau. 



The group is closely allied to LIsoacme, being distinguished merely 

 by the narrow form, generally more numerous whorls and smaller 

 aperture. 



Group of B. pupiformis. 



B. PUPIFORMIS Broderip. PI. 45, figs. 9, 10. 



Shell ri mate-perforate, long, tapering above, cylindrical below, 

 rather solid ; whitish, the earlier whorls blackish-orange or corneous, 

 or entire shell corneous with narrow irregular white streaks. Sur- 

 face smoothish, the growth-lines irregular, more prominent at sutures, 

 and there is some superficial nmlleation throughout. Whorls 10-11 , 



