266 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



Helix Piriformis, Bland, Ann. N. Y. Lye, VII. 37, Fig. (1858). — W. G. Bin- 



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



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

 Fig_162. p 1# XIX Fig 2 (1840) . Tem Mdl ( u lg6 (ex parte)> 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. 



1-2. — Pfeiffer, Mon. Hel. Viv., I. 418. —Reeve, Con. 

 enlarged. ' 



Icon. 720. 

 ? Helix Sayii, Wood, Ind. SuppL, PI. VII. Fig. 34 ; ed. Hanley, 228, Fig. 34. 



— DeKay, N. Y. Moll., 47. 

 Deeded ochila 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 latter. 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 rerlexed 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 Postelliana, espiloca, and Hazardi. 



Genitalia unobserved. 



Polygyra Postelliana, Bland. 



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

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

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



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- 

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

 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 lamelliform, scarcely oblique tooth, pro- 

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

 8^ mill. ; height, 5 mill. 



