78 Binney on Terrestrial MoUusks. 



talis, auriformis, rinfjens ; pcrist. sublabiatum, marginibus callo elevato, 

 angnlari, supprne laniinam profunde intrantem altoramque minorem 

 prope columellam (ambas profundi ferri ecjuino instar connexas) emit- 

 tente junctis, supero breviter expanse, laminam obliquam imniittente, 

 basali calloso-reflexo. [Pfeiffer.] 



SYNONYMS AND REFERENCES. 



Helix hippocrepis Pfeiffer in Roemer's Texas, p. 455; in Zeitsch. f. Mai. 

 1848, p. 119; Mod. Hel. Viv. iii. 267. 

 Chemnitz, ed. 2, ii. 33.3, pi. cxxxi. f. 4-6. 

 Eeeve, Con. Icon. No. 1238, (1854). 



DESCRIPTION. 



Animal not observed. 



Shell perforated, depressed, rather heavy, closely stri- 

 ated, opaque, smoky; spire flattened; suture impressed; 

 whorls 5|, scarcely convex, the last carinated above, more 

 convex below, falling abruptly at the aperture, and behind 

 it very much contracted and with a prominent isolated 

 bulge ; umbilicus at first expanded and grooved, but rap- 

 idly terminating in a minute perforation ; aperture almost 

 horizontal, ear-shaped, complicated with teeth ; peristome 

 white, thickened, its extremities joined by an elevated, 

 sharp, angular ridge, from which protrude far within the 

 aperture two laminae, (the upper one sharper and more 

 prominent,) the connecting terminations of which within the 

 shell resemble a horseshoe ; the upper portion of the per- 

 istome is slightly reflected and furnished with an oblique 

 entering angle, and the basal portion is callous and reflected. 



Greater diameter, 12 ; lesser, 10 ; height, 5 millimetres. 



Geog-raphical Distribution. New Brauenfels, Texas. 

 (Roiimer.) 



Remarks. The smaUer, columellar lamina, from which 

 the name of the shell is derived, is not represented in the 

 plate. 



This species is remarkably well characterized and can- 

 not be compared or confounded with any other known 

 American shell. It is very rare in cabinets. 



