54 BULIMULUS-CENTRAL AMERICAN. 



elongate-conic, the apex a little obtuse ; suture impressed. Whorls 

 6, slightly convex, the last a little shorter than spire (6i : 8), some- 

 what attenuated at base, rounded. Aperture acuminate-oval, colored 

 like the outside; peristome simple, unexpanded, the columellar 

 margin dilated, whitish, nearly closing the umbilical fissure; basal 

 and outer margins acute. Alt. 14, diam. scarcely 7 mill. ; alt. of 

 of aperture 6, width 4 mill. (. & F.). 



Variety: a little smaller, corneous-hyaline, encircled by incon- 

 spicuous, interrupted, whitish-hydrophanous lines. Alt. scarcely 

 12, diameter 6 mill. (C.&F.~). 



Bulimulus istapensis C. & F., Journ. de Conch., xxi, 1873, p. 286 ; 

 Moll. Terr, et Fluv. Mex., p. 549, pi. 20, f. 18. B. unicolor var. ista- 

 pensis MARTENS, Biol. Centr. Amer., Moll., p. 248. 



The large series of specimens from numerous localities in northern 

 Yucatan, which I refer to this species, are a variety probably near 

 to, if not identical with, istapensis. The shells when fresh are 

 brown or corneous-brown, but soon weather to whitish or corneous 

 hyaline. In almost every locality the slender and stouter forms 

 occur together, and with intermediate specimens. 



Var. PETENENSIS (Morelet). PI. 10, fig. 82. 



Shell larger, whitish with oblique streaks of brown or purple ; 

 spire darker, becoming purple toward the apex. Whorls 6. 



Alt. 18, diam. 9 mill, (specimen from Morelet). 



Alt. 19, diam. 8 mill. ; aperture 8| mill, long (type). 



Peten, north Guatemala, on blades of grass in open savannas 

 (Morelet). 



Bulimus petenensis MOREL., Testae. Noviss.,ii,p. 10. Bulimulus 

 petenensis C. & F. t. c. p. 553, pi. 20, f. 13. B. unicolor var. peten- 

 ensis MARTENS t. c. p. 248. 



More opaque than the preceding, somewhat larger, with the 

 earlier whorls deep purple. 



B. CORNEUS (Sowerby). PI. 10, fig. 68. 



Shell narrowly umbilicated, ovate-conic, thin, uniform dull brown 

 or corneous-brown ; but little shining. Surface smoothish, with 

 light growth-wrinkles. Spire conic, the apex obtuse, nepionic 

 whorls obsoletely wrinkle-granose. Whorls 5 to 6, moderately 

 convex, the last ventricose. 



