352 



1 >H YL UM A R THK OPODA . 



expands as a reservoir for the spermatozoa and serves as a copulatory 

 organ. 



3-6. Four pairs of terminally clawed 7-jointed walking legs. The 

 most anterior pair are much used as feelers. The spinnerets at the 

 end of the abdomen are modified abdominal legs. Besides these the 

 embryo has four pairs of abdominal appendages which abort. 



The nervous system is of the usual Arthropod type, but 

 shows much centralisation. Thus the ventral ganglia are 



II. 



III. 



FIG. 171. Garden Spider. 



I., Female garden-spider; II., end view of head of the .same 

 showing the simple eyes, the poison fangs (cA.) and the 

 pedipalps (/.) : III., posterior end of body showing two pairs 

 of spinnerets (sfi.), with anus above. 



fused into one large centre in the cephalothorax (see P'ig. 

 172), a condition comparable to that in crabs. There 

 are two or three rows of simple eyes on the cephalothorax, 

 whose focal distance is very short, spiders trusting most 

 to their exquisite sense of touch, by which they discriminate 

 the various vibrations on a web line. The senses of 

 smell, hearing, and taste are also present, but little is 

 known in regard to the organs. 



