278 A MANUAL OF AMERICAN LAND SHELLS. 



larly curving callus, its basal margin with a small notch. Greater di- 

 ameter 10, lesser 9™" ; height, 6""". 



Helix stenotrema, Ferussac, in Miis., teste Pfeiffek, Symb., ii, '39, escl. pnsfula. — 



Eekve, Con. Icon., 702.— W. G. Binney, Terr. Moll., iv, 61 ; L. & Fr.-W. Sh., 



i, 117 (1869).— Bland, Ann. N. Y. Lye, vii, 327, 

 Selix hirsuta, var. a, FicRUSSAC, Hist., pi. l,a, fig. 3. — /?, Pfeiffer, Mon. Hel. Viv., i, 



421 ; in Chemnitz, til. 2, i, 376 (1846), pi. Ixv, figs. 12-14 (1849), var. stenotrema. 



— Var. Binney, Terr. Moll., ii, 151, pi. xlii, fig. 4.— Deshayes, in FER.,i,140. 

 Stenotrema co7ivexa,RAFiy;Esqv¥.,'Eixnm. and Ace, 3 (1831) ; Binney and Tryon ed., 



28. 

 Stenotrema stenotrema, Tryon, Am. Jonrn. Couch., iii, 56 (1867). — W. G. Binney, 



Terr. Moll., v, 295. 



A Post-Pliocene species, now ranging over both Interior and South- 

 ern Eegions. 



In stenotrcmum the notch is invariably small and more central than 

 in hirsuium ; the parietal tooth is more produced over the aperture, 

 and its lower edge is a regular curve, not somewhat sinuous, as in the 

 latter and spinosum ; it is also curved downwards at its outer extrem- 

 ity, not terminating abruptly, as usual in those species. The form of 

 the parietal tooth, however, varies iii hirsuium, from which this species 

 can chiefly, if indeed not alone, be distinguished by the size and posi- 

 tion of the notch. 



Jaw as usual, with 8 stout, crowded ribs. 



Lingual membrane (Terr. Moll., Plate VII, Fig. E) has 20-1-20 teeth; 

 10 laterals ; the eleventh tooth having its inner cutting point bifid. 



Genitalia as in S. hirsutum, with great development of prostate, 

 penis sac, testicle, and epididymis; the last not convoluted. 



Stenotrema hirsutum, Say. 



Shell imperforate, subglobose; epidermis brownish or chestnut, 

 covered with numerous, sharj), rigid hairs ; whorls 5, rounded ; suture 

 Fig. 205.* distinct; aperture contracted, very narrow, almost closed 

 ^^ by an elongated, lamelliform tooth situated on the parietal 

 wall and extending from the center of the base, within 

 the junction of the peristome with the outer whorl, into the 

 s. hirsutum. f^^\gQ yf i]^q apcrturc ; peristome narrow, very much de- 

 pressed, and reflected against the outer \yhorl, with a deep cleft or 

 fissure near the center of the basal margin ; umbilicus wholly covered; 

 base convex ; far within the base of the shell is a transverse tubercle, 

 starting from the axis. Greater diameter 7^, lesser 7'""; height, 



* The hairy character of the epideruiis is not shown in the figure. 



