1915.] Cockerell, Gastropod Mollusca. 119 
(Lower Eocene) through the Wind R. and Green R. into the Oligocene. 
Selected specimens look like very distinct species, but there seems to be a 
great amount of variability, which is about the same in character and degree 
in the oldest as in the latest representatives. We are not in a position to 
assert positively that all these shells represent a single species (for which the - 
oldest name is veterna), and it is better to treat them as distinct, or at least 
to give them subspecific rank. 
Helix peripheria White (8882 = type), from the Eocene, Valley Range 
west of Gunnison, Utah, is an internal cast, with fragments of shell showing 
irregular flattened rib-strise. It looks immature; there are only about four 
whorls; apex lost. Itis not the young of Glyptostoma spatiosum; the upper 
whorls are too small by far. 
Pleurodonte eohippina n. sp. 
Shell flattened, lenticular, very acutely keeled; aperture rather narrow, columella 
and inner wall with a heavy callus; no umbilicus; peristome with a well-developed 
basal lamina. Alt. 5.5, max. diam. 
12.5 mm.; length of aperture about 
6.5 mm.;spire about 1.5mm. The 
spire has been worn down, so that 
the number of whorls cannot be as- 
certained; at first sight the spire Fig. 4. Pleurodonte eohippinan. sp. Type. 
seems to be covered by a thin callus, 
but this is surely the effect of wearing. A small part showing the sculpture, of rather 
well-marked but irregular riblets, about five to a mm., is preserved just behind the 
aperture. The outer upper part of the peristome is lost. | 
Sand Coulee Beds (Eocene); head of Big Sand Coulee, Sept. 9, 1912 (Granger 
and Stein.) 
This appears to be a true Pleurodonte, of the Labyrinthus type, now 
confined to the Neotropical Region. | 
FRESHWATER SPECIES. 
Physa bridgerensis Meek, variety a. 
Imperfect specimen, 15 mm. long; three miles east of mouth of Pat 
O’Hara Creek, Clark’s Fork Basin, Wyo., Sept. 18, 1912 (W. S.). 
Imperfect, crushed, specimen, 17.5 mm. long; head of Big Sand Coulee. 
Wyo.; Sept. 6-7, 1912 (W. G.). These have very fine, weak, vertical striz; 
They probably represent a species of the type of P. bridgerensis, but smaller, 
they are however too imperfect to permit the recognition of any satisfactory 
diagnostic characters. : 
