84 THE STORY OF ANIMAL LIFE 



Anhropoda which are neither Crustacea nor yet 

 Insects. Among these is the familiar spider, an 

 "insect" in popular language, but not so de- 

 scribed by the zoologist. Among other differ- 

 ences, the true spiders have eight legs, whereas 

 the true insects have only six. Fig. 19 shows a 



FlG. 19. A South American Spider, Ctenvsferus, from the 

 Amazon region, natural size. 



typical spider; the eight jointed legs are at- 

 tached to the thorax ("breastplate"); with the 

 latter the head is united. The abdomen, as in 

 insects, is formed by the fusion of several seg- 

 ments, and has no legs, but it has, however, out 

 of sight, the spinning legs or "spinnerets," out of 



