HELIX-CEPOLIS. 93 



Key to the species of Cepolis. 



Broadly umbilicated ; depressed, 



Spire slightly convex ; aperture 1-toothed, angrandi. 



Spire concave ; aperture 2-plicate within, macneili. 



Imperforate or narrowly perforate, 

 Aperture 2-toothed within, 



Peristome broadly expanded, flattened ; spire conoidal, 



pimesoma. 

 Perist. less expanded, not flattened ; spire depressed, 



Periphery obtusely angular, cepa. 



Periphery rounded, trizonalis. 



Aperture not 2-toothed ; surface rough. squamosa. 



H. CEPA Miiller. PI. 49, figs. 55-58, 62-64. 



Covered-perforate, or imperforate, globose-depressed, solid, opaque, 

 somewhat shining, chestnut brown, with a spiral light band on the 

 upper surface, lighter colored beneath ; surface obliquely striate and 

 finely rugose all over ; spire depressed, low ; apex slightly obtuse ; 

 suture slightly impressed from the beginning outward ; whorls 4* to 5, 

 the inner moderately, the last rapidly widening, and then becoming 

 narrower on its last one-fourth, then expanded at the aperture ; 

 periphery subcarinated ; base convex ; body-whorl deeply, abruptly 

 deflexed anteriorly, and with a deep furrow or pit a short distance 

 behind the aperture at the periphery ; aperture quite oblique, brown 

 within, rounded-lunar ; peristome narrowly expanded, baso-columel- 

 lar margin reflexed and adnate over the umbilicus, nearly or wholly 

 covering it, bearing within a strong square tubercle ; outer wall of 

 aperture bearing a short distance within a strong callous fold. 

 Terminations of peristome not converging, joined by a light callus. 



Alt. 20-25, diam. 37-45 mill. 



Hayti. 



H. cepa MULL. Hist. Verm, ii, p. 94. FER., Hist. t. 53 A, f. 1 , 

 2. PFR. i n Conchyl. Cab. t. 10, f. 9, 10 ; Monogr. i, p. 303. H. 

 impressa BLAINV., Diet. sc. nat. xx, p. 427. Cepolum nicolsinianum 

 MONTF. Conch. Syst. ii, p. 151. 



A small form before me measures, alt. 17, diam. 31 mill. 



H. TRIZONALIS Grateloup. PL 49, figs. 68-70. 



Imperforate or narrowly perforate, depressed-globose, strong, 

 shining, yellowish-white with three brown zones, base whitish ; sur- 



