THE SPIDER. 



147 



surface a number of simple eyes, variously arranged, 

 according to the species, but always embracing a very 

 large field of vision. Underneath the cephalo-thorax are 

 inserted eight legs, terminated by notched hooks ; this 

 number of feet is constant in the spiders, and distin- 

 guishes the latter from insects, all of which have six. 



The abdomen is attached to the anterior portion of 

 the body by a very thin stalk ; it is 

 soft and round. Behind it is furnished 

 with the spinning glands, which form 

 rounded eminences ; these are four or 

 six in number, and are pierced with a 

 large number of minute holes open- 

 ing into internal canals filled with a 

 gummy matter analogous to silk. 

 This matter produces threads of ex- 

 ceeding fineness, for more than a 

 thousand would be required to make 

 the thickness of a human hair. As 

 these threads leave the spinning 

 glands the spider, by the aid of its feet, 

 notched like combs, unites them in a 

 single filament, which it draws out SPIDER WITH THE LEGS 

 from the point at which it has first 

 attached one end by pressure of the 

 abdomen. With these threads the 

 spider weaves its web, or stretches a 

 bridge from one place to another, or 

 descends to the ground, as it desires. 

 And with the same substance it lines 

 its hiding-place, or makes the silky 

 sac in which it deposits its eggs. The long white fibres 

 sometimes seen floating in the air, and often called 



CUT OFF. The figure 

 shows the union of 

 the head and thorax 

 in one piece, forming 

 the cephalo-thorax. 

 c, chelycera; pm, 

 jaws ; pi to p 4 , the four 

 pair of feet; r, res- 

 piratory sacs ; s, stig- 

 mata ; a, anus ; /, 

 spinners. 



