. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. POLYGYRA. 287 Jaw as usual; 14 crowded ribs. P. pustula (PI. VI. Fig. E) has 17—^1—17 teeth on its lingual membrane, with 8 laterals. Polygyra pustuloides, Bland. Shell widely umbilicate, planorboid, thin, rufous or pale horn-colored, deli- cately striated, with thin, sparingly hirsute epidermis; spire scarcely elevated; whorls 4 to 4^, slightly convex, gradually increasing, the last subangular at the periphery, at the aperture gibbous, ^'^* ^^^ constricted, suddenly deflected, beneath devious; suture rather
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. POLYGYRA. 287 Jaw as usual; 14 crowded ribs. P. pustula (PI. VI. Fig. E) has 17—^1—17 teeth on its lingual membrane, with 8 laterals. Polygyra pustuloides, Bland. Shell widely umbilicate, planorboid, thin, rufous or pale horn-colored, deli- cately striated, with thin, sparingly hirsute epidermis; spire scarcely elevated; whorls 4 to 4^, slightly convex, gradually increasing, the last subangular at the periphery, at the aperture gibbous, ^'^* ^^^ constricted, suddenly deflected, beneath devious; suture rather deeply impressed; umbilicus wide, equal to one-third of the larger diameter of the shell, showing all, but espe- cially the penult whorl; aperture with an internal, fulcrum- like process on the base of the shell, oblique, crescentic, with an erect, oblique, white, parietal lamelliform tooth, joined to the upper angle of the aperture by a slightly arcu- p pustuloides. ate, filiform callus; peristome reflected, with margins ap- proaching, and having two dentiform lobes separated by a deep fissure. Greater diameter 5^, lesser^4^ mill.; height, 2^ mill. Helix pustula, Binney, Terr. Moll, II. 201, PL XXXIX. Fig. 3, not of F^rus- SAC. Helix pustuloides, Bland, Ann. N. Y. Lye, VI. 350, Fig. 3 (1858).—W. G. Binney, Terr. Moll., IV. 93 ; L. & Sh., I. 110 (1869). Dccdalochila 2}ustuloides, Tryon, Am. Journ. Conch., 111. 61 (1867). Georgia and Alabama. A species of the Southern Region. P. pustuloides is intermediate in size between pustula and leporina, — is less globose than the former, and more sparingly hirsute. It differs widely from both in the character of the umbilicus; the aperture is much like that of pus- tula, but more narrow than that of leporina. The inferior tooth on the peri- stome is more developed laterally than in jmstula, — indeed, it has a somewhat bifid appearance, in which respect it is more allied to leporina. The fulcrum in pustuloides is of th
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