December, ’23] 
BASINGER: WHITE SNAIL IN CALIFORNIA 
523 
into everything. In La Jolla they became so numerous in places that 
during the rainy season while the snails were crawling about one could 
hardly travel on the sidewalk without crunching snails at almost every 
step. 
The Infestation at La Jolla 
It is not know how or when Helix pisana was first introduced into the 
United States but one rumor credits a European resident of La Jolla 
with its introduction for the purposes of a table delicacy. This snail 
is used extensively as an article of food in France and Italy. It may have 
escaped from among a collector’s specimens, for if taken while sealed 
with a heavy epiphragm it appears quite lifeless and may, after months, 
push off the seal and crawl about again. The earliest record of its exist¬ 
ence in La Jolla is from some specimens in a collection of shells marked 
“La Jolla, June, 1914.” 
When first brought to the attention of the San Diego County Horti¬ 
cultural Office in 1918 the infestation was in the lower end of a canyon 
that runs through the southern portion of the town, and in a few of the 
adjoining lots. It covered at that time an area of about three or four 
city blocks (1). In 1922 the snails had spread throughout the whole 
length of the canyon and the adjoining properties. They were in 
twenty-two different city blocks and had a good start also at the Scripps 
Institution for Biological Research which is about two miles north of 
La Jolla. In the eradication work it was necessary to treat about eighty 
acres. This included a margin of safety beyond the actual infestation. 
Throughout a large part of the infested area the white snails were present 
in astonishing numbers. They were on virtually everything—houses, 
fences, bridges, curbings, trees, telephone poles, shrubbery, weeds and 
rock piles. In the summer they were sealed fast to the various objects 
waiting for the rainy season. Only in places that received water regu¬ 
larly was there any action among the white snails in the dry summer. 
McLean (1) counted 798 snails on a small wild buckwheat bush less 
than two feet across. In a garden plot 16 by 19Jj feet we took out 
6690 snails. This was about 21 per square foot and represented a fair 
average for much of the infested area. 
Life History and Habits 
Helix pisana is a member of the Pulmonata, a group which comprises 
the air-breathing Gasteropods. The typical shell is light buff with 
lineal brown stripes. The variation in shell color ranges, however, from 
white to buff with no marking of any kind to those having as many as 
fourteen lineal brown stripes. The usual size of the adult shell is one-half 
