ARACHNIDS. 



283 



very slight touch, — it appears ill adapted either to escape from danger 

 which threatens it on all sides, or to supply itself with food : the eco- 

 nomy of such an animal deserves our notice. 



The several small appendages, represented in fig. 124, it is import- 

 ant not to confound with each other. Of these the two longest, No. 



[Fig. 123. JUpeira diadema, or Garden, Spider, 



1, having articulated processes, seem to be feelers ; the others, being 

 the organs by which their silky threads are emitted, are four in num- 

 ber. Their structure is very remarkable ; the surface of each of the 

 spinnarets is pierced by an infinite number of minute holes, as seen in 

 No. 2, from each of which there escape as many little drops of a liquid, 

 which, drying the moment they come in contact with the air, form so 

 many delicate threads. Immediately after the filaments have passed 

 out of the pores, they unite first together, and then with those of the 

 next, to form one common thread ; so that the thread of the spider is 

 composed of a large number of minute filaments, perhapg many thou- 

 sands, of such extreme tenuity, that the eye cannot detect them until 

 they are twisted together into the working thread. In the two pairs 

 of spinnarets a difierent anatomical structure is to be detected ; the pair 

 above, which are a little longer than the lower, show a multitude of 



