AIR-BREATHERS 125 
find the sun-dial on the lawn all dotted with little 
groups of these microscopic snails. Soon after- 
wards they disappeared as suddenly as they had 
come, and I have never seen them since, though I 
presume they still live among the grass roots. Un- 
der the microscope the shell is very pretty, having 
a moderately elevated spire of four whorls, which 
are marked by fine cross ribs. The umbilicus is 
large, and the shell when inverted looks like a shal- 
low bowl. The shell is dark horn-colored, and is 
about as large as the head of an ordinary pin. 
Var. pasadénae, Pilsbry, 1s widely umbilicated, 
and is without the spaced riblets, or has them very 
shghtly indicated. Its diameter is 2mm. It was 
found in a garden in Pasadena, which fact indi- 
eates its good taste. 
Punctum randolphi, Dall, Randolph’s Dot-shell, 
has a minute, reddish brown shell with dull silky 
luster. Its four whorls are quite elevated, and the 
umbilicus is small. It is very minute, having a 
diameter of less than 2mm. It is found near the 
city of Seattle, under leaves. 
Helix aspérsa, Miull., the Spotted Snail, is a 
European species which was introduced into this 
country many years ago. It seems to thrive about 
settlements, quite unlike most of our native species, 
and in some places it has already become a source 
of annoyance, eating garden flowers and veg- 
etables altogether too freely. It is very easy to 
raise broods of the young of this species in a snail- 
ery, which may be constructed somewhat like a 
small hotbed, for they feed readily on lettuce and 
