HELIX. 



lOl 



aperture, forming a white erect lamella on the floor of the whirl, 

 parallel with, and leaving a narrow sinus between it and the inner 

 wall, to which it is joined at its extremity, about two and a half 

 mill, from the edge of the peristome. The position of this lamella 

 can be seen through the shell. 



Helix oppilata, Mokicaxd. — Shell umbilicated, depressed, deli- 

 cately striate, subpellucid, light horn-color or white ; spire scarcely ele- 

 vated ; whirls five, rather convex, gradually increasing, the last deflected 

 at the aperture, inflated below, constricted behind the peri- 

 stome ; umbilicus at first widened, then narrow, pervious; 

 aperture diagonal. Innately -circular, ringent ; peristome 

 briefly reflected, its terminations joined by a tongue-shaped, 

 entering, two-forked callus, the right margin subequally 

 bidentate. Greater diameter 7, lesser 6 ; height 3 mill. 



Helix oppifata, Moricand, Test. Noviss. I, 8.— Pfeiffek, 

 Mon. Hel. Viv. Ill, 264 ; IV, 314. 



The specimen figured is not American, nor Save I known of 

 any having been found out of Yucatan, but Pfeiffer on Shuttle- 

 worth's authority refers to Florida a var. /3 with a somewhat 

 more elevated spire, five and a half whirls and 8f mill, in the 

 greater diameter. 



Helix dorfeiiilllana, Lea.— Shell rimately umbilicated, dis- 

 coidal, slightly convex above, flattened below, light horn-colored, 

 striated, below smoother and with minute revolving lines ; spire not 

 much elevated; whirls six, flattened, gradually in- 

 creasing, the last more convex, inflated below, con- 

 stricted behind the peristome, descending at the aper- 

 ture, below with a grooved rimation of one and a half 

 ■whirls, ending in a very small umbilicus ; aperture 

 oblique, subreniform, contracted, far within furnished 

 with a deeply seated, erect tubercle on the base of the 

 last whirl ; peristome white, very much thickened, not 

 reflected, continuous, its terminations but slightly 

 approached, joined by a heavy, excavated, subquadrate 

 callus projecting across the aperture, the columellar 

 margin with a deeply seated, transverse, somewhat 

 pointed denticle, distinctly separated from a broader, equally deeply-seated 



Fig. 178. 



Helix dor/c nil liana, 

 enlarged. 



