ZONITES. 131 



ferent localities, suites of them, of different sizes, I notice that the " umbilicu s 

 small, orbicular, profound," of Say, exists only in young specimens, it being 

 closed in the full-grown shell. 



It resembles the preceding species, but has one whorl less, is more depressed, 

 and its base is more convex. The tooth in the aperture is sometimes so little 

 prominent as to be hardly visible ; at other times there are 3 teeth. The 

 strife of growth are fine and crowded, and seem to be more nearly at right 

 angles with the suture than is usual in other species. 



Jaw strongly arcuate, ends rounded ; concave margin smooth, with a stout, 

 rounded, blunt, median projection. 



Z. suppressus (PI. III. Fig. J, the marginals are from near the edge of the mem- 

 brane) has 30 1 30 teeth, with 8 perfect laterals on its lingual membrane. 



The genitalia are figured by Leidy (1. c.) as in Z. intertextus (see above). I 

 have already under Z. gularis pointed out the specific distinction between that 

 species and suppressus, furnished by the genital system. 



Zonites lasmodon, PHILLIPS. 

 Vol. III. PI. XXXVII. Fig. 2. 



Shell very much flattened above, a little convex ; epidermis corneous, shin- 

 ing ; whorls 7, narrow, very slowly increasing in diameter from the apex to the 

 aperture, and not expanding at the aperture, with minute, transverse striae and 

 wrinkles ; suture moderately impressed ; peristome thin, acute ; aperture nearly 

 circular; within, upon the base, are 2 prominent, white, testaceous laminae, 

 nearly parallel, and extending far into the cavity of the whorl; umbilicus 

 large, rather expanded, and deep ; base smooth, well rounded from the um- 

 bilicus to the circumference. Greatest diameter, 6 mill. ; height, 2| mill. 







Helix lasmodon, 1 PHILLIPS, Journ. Acad. Nat. Sci., VIII. 182 (1842) ; Proc. of 

 same, I. 28 (1841). BINNEY, Terr. Moll., II. 254, PI. XXXVII. Fig. 2. 

 DEKAY, N. Y. Moll., 47 (1843). PFEIFFER, Mon. Hel. Viv., III. 142, V. 

 216 (1868). W. G. BINNEY, Terr. Moll., IV. 122. 



Helix macilenta, SHUTTLEWORTH, Bern. Mit. 1852, 195. GOULD, Terr. Moll., 

 III. 20. PFEIFFER, 1. c. III. 640. 



Gastrodonta lasmodon, TRYON, Am. Journ. Conch., II. 257 (1866). 



Hyalina lasmodon, W. G. BINNEY, L. & Fr.-W. Sh., I. 



A species of the Cumberland Subregion, found thus far only in Eastern Ten- 

 nessee and in the mountains of Northern Alabama. 



Animal with the distinct locomotive disk, the longitudinal furrows above the 

 margin of the foot, and the caudal mucus pore characterizing Zonites. 



Jaw and lingual as usual in the genus. 



The lingual membrane (PI. III. Fig. O) has 41 1 41 teeth, with 9 perfect 

 laterals. The reflected portion of the centrals and laterals is short, as in Vitrina. 



Genitalia not observed. 



i Should not the name be rather elasmodon t 



