HELIX. 1C3 



corrugations and depressions on its surface, and the sin- 

 gular intermixture of colors, the prominent parts being 

 yellow and the depressions brown or chestnut. The 

 spire is usually more regularly striated and rufous. 

 The color internally is rufous or chestnut. 



The upper surface resembles in general aspect large 

 and coarse specimens of H. albolabris, Say. The num- 

 ber and arrangement of the whorls are the same, and 

 the size corresponds ; but the epidermis is much more 

 yellow, and the delicate and beautiful oblique striae of 

 that species are replaced by rough corrugations. The 

 body-whorl is also decidedly larger and more voluminous, 

 and the aperture is consequently larger. On the lower 

 surface the resemblance disappears ; the umbilicus being 

 open and deep, the lip much less reflected and not flat- 

 tened, and the aperture more rounded. The greater 

 capacity of the body-whorl is also more apparent on the 

 base. In size, color, and sculpture, it resembles If. 

 tudiculata, Lea, but it is more depressed, and has a 

 very different base. It is a peculiar and marked 

 species. 



30. HELIX CONCAVA, SAY. 

 PLATE XXI. 



H. testa planulata, late umbilicata, albido-cornea ; an- 

 fractibus quinis ad basim rotundatis ; apertura sub-rotundata, 

 superne depressa ; labro subtus rcflexo, supra simplici ; 

 columella brevi, callosa. 



