666 FRANK COLLINS BAKER 
VIVIPARIDAE 
Ambloxis integra (DeKay) 
A post-embryonic individual and two half-grown individuals 
occurred in the collection. Itisa common Campelona (= Ambloxis) 
in Illinois. 
VALVATIDAE 
Valvata tricarinata (Say) 
Apparently a rare species in this deposit. 
AMNICOLIDAE 
Amnicola limosa porata (Say) 
One broken shell of this common Ammnicola was noted in the 
collection. 
PLEUROCERIDAE 
Pleurocera elevatum (Say) 
This common river snail is very abundant in these deposits and 
includes the typical form together with individuals showing spiral 
lines on the base of the shell, indicating a tendency to vary toward 
the race known as Jewisitz. In some individuals the growth lines 
near the aperture are raised to form costae. All ages are repre- 
sented, and the young are strongly carinate. Hlevatwm is dis- 
tributed throughout the state. 
PLANORBIDAE 
Planorbis antrosus Conrad (= bicarinatus Say) 
Three specimens of this widely distributed species were observed 
in the collection. The single adult individual is small for the 
species. 
ENDODONTIDAE 
Pyramidula solitaria (Say) 
A single broken shell of this species of land snail was found with 
the fresh-water species, evidently a stray individual which had 
fallen or been washed into the stream. 
