28 THE NAUTILUS. 
whorls has a major diameter of 2°7 mm.; one of the variety, with 
exactly the same number of whorls, measures 4:0 mm., and my 
largest specimen 5°5 mm. 
HELICES IN ILLINOIS. 
BY W. S. STRODE. 
In the Spoon river region of central Illinois, Polygyra multilineata 
is probably the most numerous of all the Helices. In the heavily 
wooded districts bordering the banks of the stream, where rotten 
logs, decaying leaves and vegetation are in the greatest abundance, 
they attain the largest size. Further back near the bluffs they are 
much smaller, not being more than one-half the size of those found 
near the river’s bank. This difference which is due probably to 
environment, has given rise to the so-called multilineata major and 
minor. Not long since while driving across the bottom a mile from 
the river, I noticed many snails in the wagon track and crawling 
across the road. Just on my left was a tract of swamp prairie land 
containing several acres. The previous season this had grown up 
with tall prairie grass two or three feet in height, but a day or two 
before it had burned over. Going over to it I found the ground 
thickly strewn with multilineata which the fire had killed. _Wher- 
ever a bit of grass, log or rail had escaped the fire, live ones could 
be picked up by the handful. It was the most extensive snailery 
I had ever seen. Thousands of them dead and alive, but not an 
albolabris nor a profunda nor a Helix of any kind except the multi- 
lineata ; and in coloration from those that were almost albinos to 
the rubra with scores of lines, and all were the minor variety. 
Pyramidula alternata is the next species in relative abundance. 
Taking both upland and lowland it probably will outrank the mui- 
tilineata. Then comes the appressa, which in some localities is quite 
abundant. PP. hirsuta, profunda, mitchelliana and albolabris will 
rank in the order in which I have placed them. On the overflow 
land of the Illinois River a snail is rarely to be found. Further back 
near the foot-hills and on the margins of creeks tributary to this 
stream, they are quite common and fine. In these localities are to 
be found a few Polygyra elevata Say, quite rare in the Spoon River 
region. a 
