THE NATURAL HISTORY SURVEY. 309 
vex; color varying from light horn to greenish; sculpture con- 
sisting only of fine growth lines (Fig. 108); sutures impressed, 
margined by a white line which is frequently bordered by a 
dark chestnut line; protoconch consisting of one whorl, which 
is smooth and varies from porcelain-white to rather dark horn 
color; aperture rather large, oval, occupying from two-thirds to 
three-fourths of the length of the entire shell; peristome thin, 
acute, thickened on the inside by a whitish or bluish callus, 
which is bordered on the inside with red; columella almost 
straight, with a whitish callus which is sometimes lined with 
red. 
Length. Width. Aperture Length. Width. 
14.00 8.50 10.00 4.00 mill. (Rochester.) 
13.00 8.50 10.00 4,50 “ (Rochester.) 
13.50 9.00 10.50 4.50 “ (La Porte, Ind.) 
9.00 6.00 6.50 3.00 “ (18361.) 
Animal: Similar to that of gyrina. 
ys 
Fie. 108. 
Surface sculpture of PHYSA HETEROSTROPHA Say. (Original.) 
Faw and Radula: Inall respects like those of gyvina. 
Genitalia: Not observed. 
Distribution: Eastern and: Southern States; Maine to 
Georgia and west to Michigan and Illinois; Southern Canada. 
Geological distribution: Pleistocene; Loess. 
Hatitat: \n ponds and streams, adhering to sticks and 
stones and crawling over the muddy bottom. 
Remarks: During a visit to the Philadelphia Academy of 
Sciences some time ago, Mr. Pilsbry called the writer’s atten- 
tion to the fact that eterostropha had a smooth shell, while 
gyvina and some others had a shell with raised (or, as the writer 
would describe them, impressed) spiral lines. Following up 
this suggestion a large number of Phys@ have been examined 
with the result that instead of there being two species in the 
present area, as was at first supposed, there are four, with one 
or more varieties. Heterostropha is an annuan, attaining full 
maturity in one year. 
