408 THE CHICAGO ACADEMY OF SCIENCES. 
This species is known only from Berry Lake, in the south- 
ern region. 
Dr. Sterki reports that among fossils from the lower Loess 
at Freeport, Ill., he found Pistdium virginicum, variabile, com- 
pressum, fallax, cruciatum, punctatum, walkeri and (?) abdtitum. 
Pisidium virginicum, P. abditum and P. compressum have been 
dredged in Lake Superior at depths ranging from four to four- 
teen fathoms. 
162. Limnzaauricularia Linné. Text fig. 138. 
*Timne@a auricularia LINNE, Syst. Nat., Ed. XII, p. 1249. 
Shell: Roundly ovate, inflated, thin; color horny to pale 
gold; nucleus consisting of one and a half spermaceti-colored, 
smooth, rapidly increasing whorls; surface shining, lines of 
Fie. 138. 
LIMNZA AURICULARIA Linné. Natural size. 
growth fine, wavy, crowded, with occasionally a heavy ridge 
representing a rest period; whorls four, convex, inflated, the 
last large and spreading; spire short, conic, very small com- 
pared with the body whorl; sutures deeply impressed, chan- 
neled in some specimens; aperture very large, ovate, occupy- 
ing four-fifths of the length of the entire shell, rounded above 
and flaring in old specimens below; peristome thin, sharp; 
columella sigmoid with a plait across the middle, which is 
reflected over the umbilicus; umbilicus narrow, deep, nearly 
closed. The epidermis is sometimes marked by light and dark 
lines of color, alternating. 
Length, 23.00; breadth, 17.00; aperture length, 18.00; breadth, 11.00 mill. 
ef 20.00; 3 15.50; fe os 15.50; os 9.50.“ 
. 18.00; i 12.50; ‘ . 13.50; 2 8.50 “ 
Animal. Body flecked with small white spots on back of 
head and tentacles, but not on foot; mantle marked by many 
*No attempt has been made to include the synonymy of this species. 
