154 



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



Fig. 263. 



Helix sayii. 



numerous fine, oblique strise ; suture impressed; aperture lunately-sub- 

 ciicular, not dilated ; peristome white, narrow, thickened, reflected, with 

 a slightly projecting tooth on the inner edge of the 

 basal portion near the umbilicus ; parietal wall 

 with a sub prominent, white tooth ; umbilicus open, 

 deep, not wide, exhibiting all the volutions, slightly 

 contracted by the reflected peristome ; base rounded, 

 with the stiiie distinct, converging into the umbili- 

 cus. Greater diam. 27, lesser 23 ; height 17 mill. 



Eelix diodonta, Say, Long's Exped. II, 257, pi. 

 XV, f. 4 (1824) ; ed. Bixsey, 39, pi. ixxiv, f. 4.— DeKay, N. Y. Moll. 

 34, pi. ii, f. IS. — Desuayes in Fek. pi. Ixix, i, f. 2. 



Helix sayi, Binnev, Bost. Journ. Nat. Hist. Ill, 379, pi. xvi (1840) ; Terr. 

 Moll. II, 180, pi. xxiii.— Adams, Vermont MoUusca, 160 (1842).— 

 W. G. BiNNEY, Terr. Moll. IV, 70.— Pfeiffer, Mon. Hel. Viv. I, 382 ; 

 in Chemnitz, ed. 2, III, 419, tab. cxlviii, f. 13, 14.— Leidy, T. M. U. S. 

 I, 256, pi. xi, f. 1-4 (1851), anat.— Mrs. Gray, Fig. Moll. An. pi. cxciii, 

 f. 10, from Bost. Journ., no descr. — Desuayes in Fer. I, 79. — Reeve, 

 Con. Icon. no. 679 (1852).— Morse, Amer. Nat I, 98, f. 4, 5 (1^67). 



Mesodon sayii, Morse, Journ. Portl. Soc. I, 9, f. 9, pi. iv, f. 10 (1864). 



Ulostoma sayii, Tryon, Am. Journ. Conch. Ill, 38, pi. viii, f. 4 (1867). 



Fi2. 264. 



Jaw of Helix sayii. [Morse.] 



From Canada East to Michigan 

 and Maryland. 



Jaw arcuate, ends somewhat at- 

 tenuated, blunt ; anterior surface 

 with numerous stout ribs, denticu- 

 lating either margin. 



Fig. 265. 



Lingual dentitioa of Helix sayii. [Morse.] 



