296 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



A post-Pleiocene species, now ranging over both Interior and Southern 

 Regions. 



In stenotremum the notch is invariably small, and more central than in Jiirsu- 

 tum ; 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 extremity, not terminating abruptly, as 

 usual in those species. The form of the parietal tooth, however, varies in 

 hirsutum, from which this species can chiefly, if indeed not alone, be distin- 

 guished by the size and position of the notch. 



Jaw, as usual, with 8 stout, crowded ribs. 



Lingual membrane (PI. VII. Fig. E) has 20120 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. 

 Vol. HI. PI. XLII. Fig. 3. 



Shell imperforate, subglobose ; epidermis brownish or chestnut, covered with 

 numerous, sharp, rigid hairs ; whorls 5, rounded ; suture distinct ; aperture 

 contracted, very narrow, almost closed by an elongated, larnelliforin tooth, situ- 

 ated on the parietal wall, and extending from the centre of the base, within 

 the junction of the peristome with the outer whorl, into the edge of the aper- 

 ture ; peristome narrow, very much depressed, and reflected against the outer 

 whorl, with a deep cleft or fissure near the centre of the basal margin ; umbili- 

 cus wholly covered ; base convex ; far within the base of the shell is a trans- 

 verse tubercle, starting from the axis. Greater diameter, 7, lesser 7 mill. ; 

 height, 4 mill. 



Helix Ursula, SAY, Journ. Phila. Acad., I. 17 (1817) ; II. 161 ; ed. BINNEY, 8. 

 - BINNEY, Bost. Journ. Nat. Hist., III. 365, PI. X. Fig. 3 (1840) ; Terr. 

 Moll., II. 150, PI. XLII. Fig. 3, excl. stenotrcma. DEKAY, N. Y. Moll., 

 36, PI. III. Fig. 27. GOULD, Invertebrata, 175, Fig. 116 (1841). FERUS- 

 SAC, Tab. Syst., 38 ; Hist., PI. L. a, Fig. 1. DESHAYES in LAM., VIII. 113 ; 

 ed. III. 308 ; Encyl. Meth., II. 253 (1830); in FER., I. 140. MRS. GRAY, 

 Fig. of Moll. An., PI. CXCIII. Fig. 8, ex Bost. Journ. PFEIFFER, Mon. Hel. 

 Viv., excl. var., p, I. 421 ; in CHEMNITZ, ed. 2, excl. var., I. 374 (1846), PI. 

 LXV. Figs. 9-11 (1849). REEVE, Con. Icon., No. 714 (1852). LEIDY, T. 

 M. U. S., I. 257, PI. XI. Figs. 5, 6 (1851), anat. W. G. BINNEY, Terr. Moll., 

 IV. 62 ; L. & Fr.-W. Sh., I. 118 (1869). BLAND, Ann. N. Y. Lye., VII. 327. 

 MORSE, Am. Nat. I. 151, Figs. 14, 15 (1867). GOULD and BINNEY, Inv. of 

 Mass. (2), 417 (1870). 



Helix sinuata, y, GMELIN (teste PFEIFFER). 



Helix isognomostomos, y, GMELIN (teste PFEIFFER). 



