152 PROCEEDINGS OF THE ACADEMY OF [March, 
the last whorl; it is less depressed, and the aperture is perceptibly less 
broad, more roundly lunate. The differences seem sufficient to call for 
subspecific separation. The Texan and Floridian areas of distribution 
seem to be separated, so far as our present data 
indicates. V. dalliana should be looked for along 
the northern border of the Gulf. It is known now 
from peninsular Florida only. 
Vitrea dalliana™ and roemeri are much smaller 
than V. hammonis, and seem to replace that in the 
Austroriparian and Lower Sonoran zones. When 
originally described it was compared with Zonitoides 
oe arborea (Say), but it is not really related to that but 
to the hammonis group. In fact V. hammonis, 
ve binneyana and dalliana form a group of very closely 
related species. In a large number of V. dalliana 
examined from several localities, the largest shell 
measures, alt. 1.6, diam. 3.2, width of umbilicus 
Fig. 9.—V. dalliana. -/9, aperture 1.4 mm. wide, 1.2 high. This shell, 
from Osprey, Manatee county, Fla., is here figured. 
The figures do not represent the fine and beautiful sculpture of the 
surface. 
Vitrea milium meridionalis n. subsp. 
Similar to V. malium but larger, diam. about 1.75 mm., with nearly 
3% whorls, the first one finely, distinctly lirate spirally, the last whorl 
with oblique wrinkles much coarser than in miliwm, more or less an- 
astomosing, and fine spiral striz, the latter distinct on the base. 
V. milium with the same number of whorls is smaller and more 
finely wrinkled, and in Maine and Ohio shells spirals on the first 
whorl are excessively weak or wanting, not deeply engraved to the 
tip, as in Texas shells. 
Texas: San Marcos, in drift of Sinking creek, in the limestone hills; 
along the Guadalupe river above New Braunfels (type locality); 
Hondo river, Medina county ; drift of Pecos river. (Pilsbry and Ferriss.) 
New Mexico: Cloudcroft, Sacramento mountains (Viereck); Santa 
Fé (Ashmun). 
Arizona: Huachuca mountains (Ferriss); Walnut Gulch near Jer- 
ome (Ashmun). 
Specimens from Baldwin and Clarke counties, Ala. (C. B. Moore), 
4 Zonttes dallianus Simpson, Pilsbry, Proc. A. N. 8. Phila., 1889, p. 83, pl. 3, 
figs. 9-11. 
