140 



LAND AND FRESH-WATER SHELLS OF N. A. [PART J. 



In color it is also very variable, sometimes it is found of an uni- 

 form red, at others albino. 

 Fig. 235. j^^ arcuate, of uniform width ; ends blunt ; 



'fT|||ft|k anterior surface with numerous, crowded ribs, 

 " denticulating either margin. 



The teeth on the lingual membrane are arranged 

 42 — 1 — 42 ; centrals with a long, acutely-pointed 

 middle cusp, and an enlargement at either side of its base ; laterals 



] Fig. 236. 



Jaw of Helix 

 muUilineata. 



Lingual deatitioa of Helix muUilineata. 



with a long, acutely-pointed cusp, and a short, obsolete side-cusp ; 

 uncini large, irregularly bidentate or tridentate. 



Fia. '237. 



Helix peniisylvanica, Geeen. — Shell imperforate, convex, ele- 

 vated ; epidermis yellowish horn-color, or russet ; whirls six, convex, with 

 crowded, elevated, oblique strise ; suture distinctly 

 marked; aperture subtriangular, contracted by the 

 peristome ; peiistome white, narrow, reflected, not 

 flattened, with sometimes a slight thickening on the 

 inner side near the base; utnbilical region indented. 

 Greater diam. 17, lesser 15 ; height 11 mill. 



pennsylviiniea. 



Helix pcnnsylvanica, Gkeen, Contributions to Macl. 



Lye. No. 1, S. — Binney, Bost. Journ. Nat. Hist. 



I, 483, pi. xvi (1837) ; Terr. Moll. II, 105, pi. vii. 

 — Pff.iffer, Symbols, II, 3(5 ; Mon. Ilel. Viv. I, 291 (excl. //. clauita) ; 

 IV, 321 ; in Chemnitz, ed. 2, II, 51, t. Ixxiii, f. 4, 5 (excl. H. clattsa). — 

 DeKay. N. Y. Moll. 41, pi. iii, f. 35 (1843;.— Mrs. Gray, Fig. Moll. 

 An. pi. ccxci, f. 5, from Bost. Journ., no descr. — Reeve, Con. Icon, 

 no. G7G (excl. syn.).— Bland, Ann. N. Y. Lye. VI, 299 (1858).— 

 W. G, BixxEY, Terr. Moll. IV, 45. 



