396 THE CHICAGO ACADEMY OF SCIENCES. 
Animal: Not examined. 
Distribution: Lilycash Creek, near Joliet. (Collected by 
J. H. Handwerk.) 
Geological distribution: Unknown. 
Habitat: Ina small creek, in soft mud. 
Remarks: This variety was referred to Dr. V. Sterki by 
Mr. Handwerk, and considered by him to be an unusual form of 
striatinum, but he did not consider it distinct from the typical 
form. After examining a large number of specimens, the writer 
has concluded that it is a form distinct enough for a specific 
name. Its beautiful polished surface and inflated shell will at 
Fic. 187. 
SPH#ZRIUM LILYCASHENSE Baker. Natural size. 
once distinguish it from striatinum. It is shaped differently 
from stamineum and the beak sculpture is very much finer. 
Another form is found associated with the variety which 
is in a sense intermediate between the typical form and the 
variety, having a more oval shell than the type, but not being 
so much inflated; it is very dark chestnut or dark brown incolor. 
Several specimens of this form had the hinge wholly or partly 
inverse. 
p. 120. 
43. Calyculina transversa Say. 
This species has been found abundantly in the Desplaines 
River (J. H. Handwerk), and in Lake Michigan (Dr. H.N. 
Lyon). 
p. 126. 
47. Pisidium abditum Haldeman. 
This species has been found in large numbers in Lilycash 
Creek and at Smith’s Bridge, eleven miles southwest of Joliet. 
