2G8 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



Sullivan's Island, South Carolina; St. Simon's Island, Georgia ; Indiano'a, 

 Texas ; New Orleans. It seems, therefore, to range over the Southern 

 Region. 



In the form of the parietal process it is intermediate between P. Postelliana 

 and P. avara, but most like the latter ; the teeth on the peristome are very similar 

 to those in the former, but beneath it is less inflated, the umbilical region is 

 wider, showing more of the penultimate whorl, and it is hirsute. 



Jaw as usual in the genus ; 10 ribs. 



Lingual membrane (PI. VI. Fig. P) with 25 — 1 — 25 teeth, with 11 laterals. 

 The inner cutting point of the marginals is simple, not bifid. 



Genitalia not observed. 



Polygyra avara, Say. 



Shell rimately umbilicated, depressed-convex above, convex below, striated, 

 especially near the aperture, horn-colored, thin, covered with numerous short, 

 robust hairs ; spire convex, not much elevated ; whorls 4, rounded, 

 Fig. 166- 1 t | ie j ast more con vex, constricted .behind the peristome, not 

 grooved within the moderate umbilicus ; aperture very oblique, 

 subreniform, contracted ; peristome white, acute, elevated, con- 

 tinuous, its terminations connected by an elevated, oblique angu- 

 p. avara, i ar f ld ; the columellar margin furnished with two projecting, 

 obtuse, curved teeth, separated by a deep sinus. Greater diam- 

 eter 7, lesser 6 mill. ; height, 3 mill. 



Polygyra avara, Say, Nich. Encycl., 3d Am. ed (1819); Journ. Phila. Acad., I. 

 277 (1818), ed. Binney, 11. — DeKay, N. Y. Moll., 47 (1843). 



Helix avara, Ferussac, Hist, PI. L. Fig. 2. — Pfeiffer, var. /3 minor, Mon. 

 Hel. Viv., I. 418 (ex parte). — Deshayes in Fer. Hist, II. 78, PI. L. Fig. 2.— 

 Chemnitz, ed. II. 370 (ex parte), excl. Fig. — Reeve, Con. Icon (ex parte), 

 No. 720, excl. Fig. — Bland, Ann. N. Y. Lye, VII. 30, Fig (1858). — W. G. 

 Binney, Terr. Moll., IV. 74 ; L. k Fr.-W. Sh., I. 91 (1869). 



Dazdalochila avara, Tryon, Am. Journ. Conch., III. 155 (1867). 



St. John's River, Florida, " in Mr. Fatio's orange-grove " (Say). The lo- 

 cality is near Remington Landing. 



P. avara, Say, may be readily distinguished by its smaller size, more delicate 

 texture, and less globose form ; it has from 4 to 4| whorls, and is the only 

 species of the group which is hirsute, except P. espiloca. The superior tooth 

 on the peristome is armed with a hook, as in the other species, but is narrower, 

 less deeply seated, and more erect ; the inferior one is rather a distinct tooth 

 than a lamellar fold. The parietal process differs entirely from that of P. au- 

 riculata, as plainly shown in the figure. P. avara is without the groove on the 



l The slria^m Fig. 165 are incorrectly represented : they should have been shown only 

 at the termination of the last whorl, over a small space immediately behind the peristome. 



