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CHAPTER VII 
AIR-BREATHERS 
For a while we must now !eave the sea and all 
the plentitude of life that finds its home along the 
shores of the ocean, and search for the mollusean 
forms that live upon the dry land. By their very 
nature, however, we need not expect to find them 
where they have no chance to obtain considerable 
-moisture, for in dry climates they are liable to per- 
ish, even if once introduced. So we will search for 
them in the shade of forests, around springs and 
brooks, and in damp, dark places where the sun 
seldom shines. For many of them have a strong 
aversion to sunlight, especially if it is bright, and 
so they come out of their lurking places and se- 
eure their food in the night, and when morning 
comes they have disappeared. 
Most of them breathe by means of a simple lung, 
or air-sack, which opens on the right side of the 
body, as is plainly shown in the picture of the 
yellow slug, Figure 102. 
Figure 99 represents a view of an 
unusual form of Selenites vancou- 
verénsis, Lea, the Northern Selen, 
(Macrocyeclis vancouverensis). The 
unusual feature may easily be seen, for the figure 
represents the shell as sinistral, while most if not 
all of the actual specimens are dextral. Seen in 
Fig. 99 
