160 
NATURE’S CRAFTSMEN 
covered the young snail in the first days of its 
career. How carefully and wisely it builds as 
time goes on! The color of the shell is deter¬ 
mined by the skin covering which protects it care¬ 
fully so long as the little animal lives. This skin 
may be smooth, rough or hairy. The particular 
family to which the snail belongs is distinguished 
by its color, size, and the number of whorls. For 
example, there are two kinds of pond snails, 
known as 4 right-handed,’ and 4 left-handed,’ ac¬ 
cording to the direction which the coil turns from 
the apex. The left-handed species are the most 
numerous in our streams; their scientific name is 
the Physa. They do well in a jar of water, and 
I shall try to find a specimen for you. The eggs 
will be laid in a transparent mass of jelly on the 
side of the glass, and we shall have the pleasure of 
watching the young come forth. The beating of 
the heart is easily seen some hours before the egg 
hatches. I.have often noted pond snail eggs 
sticking to boards and stones in quiet waters. 
Indeed, I would not be greatly surprised if there 
were some clinging to the bottom of our boat 
right now. 
44 Snails are found all over the world. In Eu¬ 
ropean countries, especially in France and Italy, 
several kinds of snails are used for food. They 
are frequently to be seen pictured on the sign¬ 
boards of restaurants. Often the food which 
