948 The American Naturalist. [November, 
the water is so clear that the fishes can be seen darting hither 
and thither, even when they are of considerable depth. 
As to climate, the following data taken from Dr. Otto 
Lerch’s “ Preliminary Report upon the Geology of the Hills of 
Louisiana, etc." (1892), may be of interest. 
Mean Temperature at Shreveport, La., for each Month the past 
Twenty Years, from 1871 to 1890, inclusive. 
E ERE 
fe A UE ; Bo 
Du a Ro du - t n 4 2 d 
3 98 S Hog 5 $ b: 5B 
See X o Ww n Y" o o 95 0 
45.8 51.5 58.1 66.1 73.3 79.9 82.7 81.5 74.8 65.4 54.2 49.5 65.2 
The latest frost in the spring ranges from Feb. 14 to April 
9; it usually occurs the latter part of March or within the 
first few days of April. The earliest frost ranges from October 
7 to November 18—it usually comes toward the latter part of 
October. The highest temperature in the summer ranges 
from 91? F. to 107? F.; ordinarily it is between 98? F. and 
104° F. In winter the temperature rarely falls below 12° F. 
Total Precipitation at Shreveport, La. Average of each Month the 
past Twenty Years, from 1871 to 1890, inclusive. 
p * Lr 
B a UM. E 
s o8 5 B Ns mu» z E 
$39 d (d 4 B d 5^ $2 9 D P aH 
"IE. d GM wx ww o cx £O 
4.93 4.62 4.74 5.55 4.47 3.69 3.74 2.05 4.30 3.52 4.88 4.81 4.30 
As one goes south and nearer the seashore from Shreveport, 
corresponding changes in the temperature, etc., take place. 
LAND MOLLUSKS. 
_ LIMACID E. 
ZONITES. 
Zonites (Hyalina) arboreus Say, extremely abundant, being 
found under damp rubbish throughout the section. 
