THE NAUTILUS. 125 
the later deposits the new form is the only large Planorbis found, 
an interesting case of distribution in point of time in the same 
locality. 
Whether the new Planorbis is to be considered a variety of 
trivolvis or a distinct species the writer is not prepared to decide 
at the present time. In the material examined, both fossil and 
recent, there are no intermediate specimens. Until more is 
known it had better be considered a separate species. 
A NEW FORM OF AMNICOLA FROM THE OHIO PLEISTOCENE DEPOSITS 
WITH NOTES ON A PHYSA FROM THE SAME FORMATION.* 
BY FRANK C. BAKER. 
Recently, Dr. M. M. Leighton, of the Department of Geology 
of the University of Illinois, placed in my hands for study a 
large collection of Pleistocene fossil mollusks from a marl de- 
posit near Rush Lake, Logan County, Ohio. One of the species 
represented appears to be a new race of a recent species. The 
deposit is in the older Wisconsin drift. A paper is in prepara- 
tion describing the fauna of this deposit as well as that of a 
possibly older deposit in Bartholomew County, Indiana, in both 
of which a number of interesting cases of distribution occur. I 
am indebted to Dr. H. A. Pilsbry and Dr. Bryant Walker for 
assistance in determining the affinities of the species discussed 
in this paper. 
AMNICOLA WINKLEYI LEIGHTONI n. var. 
Shell differing from A. winkleyi in being larger, heavier, wider 
in proportion to its height, the body whorl being more globose 
than in the typical form; there are 44 whorls, the upper part of 
which is somewhat flat-sided just below the suture; this is 
especially marked on the last whorl of some individuals; the 
spire whorls are rounded and the sutures deeply impressed; the 
first whorl is flatter than in winkleyi ; the umbilicus is wider and 
deeper and the aperture is wider in proportion to its height than 
in winkleyi. 
* Contribution from the Museum of Natural History, University of Illinois, 
No. 10. 
