THE SCAFFOLDING LEFT IN THE BODY 107 



to move to the food. This and other correlated 

 circumstances call for far less mechanism in the 

 body, and, as a matter of fact, all the simplest 

 forms of life at the present day are inhabitants of 

 the water. 



A successful attempt at coming ashore may be 

 seen in the common worm. The worm is still so 

 unacclimatized to land life that instead of living on 

 the earth like other creatures, it lives in it, as if it 

 were a thicker water, and always where there is 

 enough moisture to keep up the traditions of its 

 past. Probably it took to the shore originally by 

 exchanging first the water for the ooze at the 

 bottom, then by wriggling among muddy flats when 

 the tide was out, and finally, as the struggle for 

 life grew keen, it pushed further and further inland, 

 continuing its migration so long as dampness was 

 to be found. 



More striking examples are found among the 

 molluscs, the sea-faring animals par excellence of 

 the past. A snail wandering over the earth with 

 a sea-shell on its back is one of the most anomal- 

 ous sights in nature — as preposterous as the spec- 

 tacle of a Red Indian perambulating Paris with a 

 birch canoe on his head. The snail not only 

 carries this relic of the sea everywhere with it, but 

 when it cannot get moisture to remind it of its 



