PAPERS ON ZOOLOGY 173 
milion Co. The White Heath specimens are very dark, almost 
brick red in color. This species is usually found at the base of 
tree trunks and about logs, and among fallen leaves. A few 
times, in November, I noticed them in small cavities in the sur- 
face of the soil. It is usually associated with Zonitoides arbo- 
reus, Pyramidula alternata and Polygyra thyroides. Circinaria 
concava is often present as an intruder, as is evident from the 
number of empty shells of this Polygyra. 
This Polygyra is very shy in nature, its movements slow, and 
as a rule very careful. The shell is carried back of the center 
of the animal and lies almost flat. The least disturbance causes 
the animal to retreat into its shell. Upon coming out again, it 
apparently uses much caution. Shrews eat this Polygyra quite 
often. In the burrow of one shrew, under a log, 93 empty shells 
of pennsylvanica were found. Of these, 42 (or 48%) had the 
spires broken by the shrew. It would appear that due to the 
extreme shyness of this snail, the shrew is obliged to break the 
shells in order to get at the animal. In this same place were 
154 empty shells of P. thyroides of which only 23 or 16% had 
the spires broken. The habits of thyroides will be discussed in 
their proper place, suffice it to say here that this snail is bolder, 
and hence the shrew gets its choice meal with a minimum ex- 
penditure of effort. 
94. P. thyroides (Say)—White Heath, Piatt Co., Brown- 
field and Cottonwood Woods, Champaign Co., Muncie and Hil- 
lery, Vermilion Co. About half of the specimens found were 
dentate. This species is our commonest of the larger helices, 
and is typical of the mesophytic woods. It endures conditions 
entering into the xerophytic and hydrophytic associations, but 
is able to get along much better in the wet than in the dry. Dry- 
ness causes it to aestivate. In the Cottonwood Woods it was 
very abundant. This woods is damper than the Brownfield. I 
found that in woods that were dry, though not exactly xero- 
phytic, that there was a tendency among the thyroides to ap- 
proach the subspecies bucculenta. While typically a ground 
species, thyroides has been found to ascend tress, having been 
found as much as ten feet from the ground. In this respect it 
resembles Pyramidula alternata. 
Sag eee 
ee ee ee ee ae ee Pe ee 
