io6 JUNGLE ISLAND 



any further care of them. They crawl away and 

 find their own food. 



From Figure 44 you can see the long, wormlike 

 body, but you cannot see that the legs are hollow 

 as they always are in legged worms. The hidden 

 arrangement of muscles under the skin fits the 

 needs of a soft-legged worm, but would never 

 do for a hard-shelled insect. 



After Sedgwick 



Fig. 44. Peripatus 



The jaws grow like those of an insect, but 

 Peripatus has only one pair of jaws and most 

 insects have more, Peripatus has a real heart, 

 which the worms have never had. The heart 

 is built like that of an insect, and so are the air 

 tubes with which it breathes. Worms breathe 

 through their soft skin or by tiny gills on their 

 legs or heads. 



This insect-worm combination seems to be an 

 experiment that Nature tried once and found 

 neither poor enough to throw away entirely nor 

 successful enough to become important and wide- 

 spread. From other experiments came the true 

 insects, and many failures must have died off. 

 Our great reason for being interested in Peripatus 

 is that it lives today and shows us what that old 

 experiment was like. 



