84 THE SCAFFOLDING LEFT IN THE BODY. 



stances calls 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 unac- 

 climatized 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. Prob- 

 ably 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 mol- 

 luscs, the sea-iaring animals par excellence of the past. 

 A snail wandering over the earth with a sea-shell on 

 its back is one of the most anomalous sights in nature 

 as preposterous as the spectacle of a Red Indian 

 perambulating Paris with a birch canoe on his head. 

 The snail not only carries this relic of the sea every- 

 where with it, but when it cannot get moisture to 

 remind it of its ancient habitat, it actually manufact- 

 ures it. That the creature itself has discovered the 

 anomaly of its shell is obvious, for in almost every 

 class its state of dilapidation betrays that its up-keep 

 is no longer an object of much importance. In nearly 

 every species the stony houses have already lost their 

 doors, and most have their shells so reduced in size 

 that not half of the body can get in. The degenera- 

 tion in their cousins, the slugs, is even more pathetic. 

 All that remains of the ancestral home in the highest 



