288 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



Jaw as usual in the genus ; over 10 ribs. 



Lingual membrane with 1 7 1 1 7 teeth, 8 laterals, the ninth tooth having 

 bifid inner cutting point (PL VI. Fig. C). 

 Genitalia unobserved. 



Polygyra leporina, GOULD. 

 Vol. m. PI. XL. a, Fig. 1. 



Shell with a partially covered umbilicus, depressed, orbicular, thin, reddish 

 horn-color, delicately striated, and, when fresh, having a delicate down on its 

 surface ; spire depressed, composed of 5 slightly convex whorls, the last of 

 which is obtusely angular at its upper portion ; base convex, excavated at the 

 umbilical region, with a minute, partially covered umbilicus ; aperture oblique 

 lunate ; peristome incumbent, rose-colored, reflexed, bearing on its dilated 

 basal edge two expanded teeth separated by a deep, narrow fissure, its termi- 

 nations joined by a quadrate, erect, oblique lamella, whose upper edge is joined 

 to the upper angle of the aperture by a thread-like callus ; an internal, fulcrum- 

 like tubercle, with uneven outer edge, on the base of the shell. Greater diam- 

 eter 6, lesser 5| mill. ; height, 3 mill. 



Helix leporina, GOULD, Proc. Bost. Soc., III. 39 (1848) ; in Terr. Moll., II. 199, 



PL XL. a, Fig. 1. REEVE, Con. Icon., 722 (1852). BLAND, Ann. N. Y. 



Lye., VI. 348 (1858). W. G. BINNEY, T. M., IV. 92 ; L. & Fr.-W. Sh., I. 



Ill (1869). PFEIFFER, Mon. Hel. Viv., IV. 320, no descr. 

 Helix pustula, PFEIFFER, Mon. Hel. Viv., I. 70, descr. : var. /3 ; III. 268, not of 



FERUSSAC. 

 Dccdalochila tywrina, TRYON, Am. Journ. Conch., III. 61 (1867). 



Indiana, Illinois, Arkansas, Mississippi, Marengo County, Alabama, Georgia, 

 Texas. A species of the Southern Region, ranging quite into the Interior 

 Region. 



P. leporina is larger than pustula, less elevated, the whorls are less convex, 

 the incremental strias less numerous and distinct, and the aperture is wider. 

 The umbilicus is more nearly covered by the peristome, and is without the 

 groove which prevails in pustula. Within and near the aperture there is what 

 may be called the fulcrum, extending from the floor of the last to that of the 

 penultimate whorl, and approaching in character to, but less strongly devel- 

 oped, than that in Stenoirema monodon. The outer edge of this fulcrum is 

 uneven, in one specimen somewhat denticulated. 



Genitalia not observed. 



Jaw as usual ; over 1 1 stout, separated ribs. A strong upper muscular 

 attachment. 



Lingual membrane as usual in the subgenus (PL VI. Fig. F). Teeth 

 18118, with 8 laterals. 



