136 



LAND AND FRESH-WATER SHELLS OF N. A. f PART I. 



Moll. 45 (1843).— Mks, Gray, Fig. of Moll. An. pi. ccscl, f. 1, from 



Bost. Journ., no descr. — W. G. Binney, Terr. Moll. IV, 43. — Pfeiffer, 



Mon. Hel. Viv. IV, 320. 

 Helix albolahris, van, Ferussac, Hist. pi. xliii, f. 4 ; pi. xlvi, a, f. 7. — 



Desuayes in Fer. part. — Pfeiffer, Symbolje, II, 22; Mon. Hel. Viv. 



I, 290 ; in Chemnitz, ed. 2, I, 81. — Reeve, Con. Icon. G56. — Blaxd, 



N. Y. Lye. VI, 359. 

 Mesodon major, Tryon, Am. Journ. Couch. Ill, 43, pi. viii, f. 5 (1867). 



Tennessee, Alabama, Florida, Georgia, and South Caroliaa. 



It is much more globose than H. albolabris, of a coarser and 

 more solid texture, and the strice of increase are much more 

 raised and prominent, so much so, indeed, as to leave distinct 

 grooves between them. The revolving striae, so distinct ou that 

 shell, are either wanting or very indistinct. The aperture is 

 smaller in proportion to the size of the shell, less flattened 

 towards the plane of the base, and more rounded. The parietal 

 wall and umbilicus are in many instances covered with a smooth 

 and shining, semi-transparent, testaceous callus. The margin 

 of the peristome is thickened, the peristome itself is narrower, 

 less abruptly reflected, and not so much flattened, and there is 

 often a tooth-like process on the inner and upper side of the 

 margin near the umbilicus. The color of the epidermis is 

 generally much darker. The only considerable variation in the 

 characters of the shell is caused by the depression of the spire in 

 some individuals, and indeed in all specimens from certain locali- 

 ties. In its most perfect condition it is often subconical. It is 

 subject to some irregularities in the form of the aperture, and 

 there is sometimes an indication of pale bands in the epidermis 

 of the body-whirl. 



Ilclis aSbo'abris, Say. — Shell imperforate, convex; epidermis 

 immaculate, of a uniform yellowish-brown, russet, or light chestnut- 

 color; whirls between five and six, with fine parallel striae raniiiug 

 obliquely across them, aiid spirally striated with very minnte and deli- 

 cate, but distinct, wavy, impressed lines, which are most apparent on the 

 hack of the reflected peristome ; suture well marked and distinct ; aper- 

 ture contracted by the peristome; peristome white, flattened in the plane 



