316 



ARACHNIDA. 



the consummation of his purpose, did he not exercise the most 

 guarded caution and circumspection in making his advances. 



Fig. 146. 



(363.) One peculiar characteristic of the Araneida is the posses- 

 sion of a spinning apparatus, whereby the threads composing their 

 web are manufactured. The instruments employed for this purpose 



F iff. 147. 



are situated near the posterior extremity of the abdomen, and 

 consist externally of four spinnerets, and twopalpiform organs (fig. 

 147 A, B). Each spinner 'et, when highly magnified, is found to 

 be perforated at its extremity by innumerable orifices of extreme 

 minuteness (^/zg.147, c), through which the filaments are drawn ; so 

 that, unlike the silk of the caterpillar, the thread of the spider, 

 delicate as it is, is composed of hundreds of smaller cords, some- 



