2G6 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



Helix auriformis, BLAND, Ann. N. Y. Lye., VII. 37, Fig. (1858). W. G. BIN- 

 NET, L. & Fr.-W. Sh., I. 88 (1869). 



Helix auriculata, BINNEY, Bost. Journ. Nat. Hist, (ex parte), 

 pl X1X Fig 2 (18 4 ). Terr- Moll-j IT 186 (ex p ar te), PI. 



XL. Fig. 1 (right hand), 2. REEVE, Con. Icon., 700. 

 DESHAYES in FER., Hist., var. minor, PI. L. Fig. 3. 

 Helix avara, CHEMNITZ, ed. 2, 370 (ex parte), T. LXV. Figs. 



P. auriform is, 1 - 2. PFEIFFER, Mon. Hel. Viv., I. 418. REEVE, Con. 



< ' 1 1 1 ; 1 1'u, ' '< I 



Icon. 720. 

 ? Helix Sayii, WOOD, Ind. Suppl., PI. VII. Fig. 34 ; ed. HANLEY, 228, Fig. 34. 



-DEKAY, N. Y. Moll., 47. 

 Dcedalochila auriformis, TRYON, Am. Journ. Conch., III. 155 (1867). 



Inhabits the Southern Region. From Texas to Georgia it is an extremely 

 common species. Immense beds of semi-fossil specimens are found in middle 

 Alabama. 



This species is common in American cabinets, and usually labelled P. avara, 

 or var. of P. auriculata, but it appears entirely distinct. It is most nearly allied 

 to the former, but is larger, not hirsute, and has the groove in the last whorl 

 within the umbilical region like the hatter. The parietal fold is somewhat 

 similar to, but does not descend so far into the aperture as that of P. Postelliana, 

 but the teeth on the labrum are in form and position, though more developed, 

 rather like those of P. avara. They are separated by the same deep sinus, but 

 the upper one generally without the sharp reflexed hook at its termination. 



Jaw as usual in the genus ; ribs numerous. 



The lingual membrane (PI. VI. Fig. R) has 26 1 26 teeth, with 8 laterals. 

 Fig. c shows the proportional greater development of the cutting point in the 

 outer laterals. The change from laterals to marginals is not formed by the 

 splitting of the inner cutting point, which remains simple to the extreme outer 

 margin. This peculiarity is shared by Posteliiana, espiloca, and Hazardi. 



Genitalia unobserved. 



Polygyra Posteliiana, BLAND. 



Shell rimately perforate, above slightly convex, with rib-like striae wider 

 apart and more prominent behind the aperture ; beneath inflated, convex, 

 almost smooth, and with microscopic spiral lines ; brown horn- 

 color, thin, shining, subpellucid; whorls 5, gradually increasing, 

 rather convex, the last deflected and turned outwards from the 

 preceding one, scrobiculate, constricted, grooved within the um- 



,.,.,. . j , ,. , P. Posteliiana, 



bilical region ; suture impressed ; aperture oblique, ear-shaped, enlarged 

 contracted ; peristome white, acute, continuous, the margins 

 joined by a tongue-shaped fold, excavated above, entering into the aperture, 

 the right margin having a deeply seated lamella, which terminates in a re- 

 flexed hook, the base with an erect lamelliforin, scarcely oblique tooth, pro- 

 duced into and recurved within the aperture. Greater diameter 9^, lesser 

 8J mill. ; height, 5 mill. 



