ee 



A MANUAL OP AMERICAN LAND SHELLS. 



Tig. 24. 



Zouites milium, Morse. 



Shell widely umbilicated, depressed, transparent, shining, white, with 

 a greenish tinge, marked with distinct and regular strite of growth and mi- 

 Fin. 23. croscopic revolving lines, the latter more conspicuous below ; 

 spire but slightly elevated ; whorls 3, rounded, rajiidly in- 

 creasing, the last planulate above, widely umbilicated be- 

 low ; aperture very oblique, subcircular, remote from the 

 axis ; i^efistome simple, acute, its terminations somewhat 

 approached, that of the columella not retiected. Greater 

 diameter l^"*" ; height, ^""". 



Relix milium, MoRSE, Proc. Boat. Soc, vii, 2-^ (1859).— W. G. Binxey, Terr. Moll., iv, 

 101, pi. Ixxix, 4, 5.— Morse, Amer. Nat., i, 543, fig. 3(3 (1867). 



StriaUira miUiim, Morse, Jouru. Portl. Soc, i, 18, ligs. 41, 42, pi. vii, fig. 43 (18G4). 



PseudolujaUna milium, Tryox, Am. Jouru. Conch., ii, 265 (1866.) 



EyaUna milium, W. G. Binney, L. & Fr.-W. Sh., 1, 38 (1869).— Gould aud Binney, 

 luv. of Mass., ed. 2, 401 (1870). 



Zonites milium, W. G. Binney, T. M., v, 119. 



Massachusetts aud Maine ; Campbell County, Kentucky. It has also 



been noticed in Monterey, 

 near San Francisco, and 

 Nevada County, Califor- 

 nia. I doubt not that it 

 will be found over the 

 whole continent. 



Morse's original figure 

 is given above. 



The surface of the shell 

 is raised in numerous rib- 



Lingual dentitiou of Z. milium. (Morse.) like folds freouentlv au- 



astomosing; longitudinal ribs reticulate the surface and render the folds 

 so crenulated that in certain lights the shell appears as if ornamented 

 with strings of beads. This peculiar character disappears at the base 

 of the shell, and is replaced by revolving lines and regular lines of ac- 

 cretion. 



Genitalia not observed. 



Z. milium is described by Morse as having 68 rows of 17-1-17 teeth 

 on its lingual membrane, with only 2 jjerfect laterals. The next six 

 teeth are shown to be bifid, not only the one or two transition teeth, but 

 the decided marginals. I have also drawn the membrane of this spe- 

 cies (T. M., V, Plate III, Fig. M). I found 18-1-18 teeth, with 3 laterals. 



