2 PRESIDENTIAL ADDRESS : 



* 5 -Harvest Spiders ( Phalangidea), in which the respiration is 

 by trachea; the abdomen is not distinctly separated from the 

 cephalothorax, and the maxillary palpi have only one claw. 



e.^Fhrynidea, in which respiration is by air-chambers, and 

 there is no post-abdomen. 



^.—Solpugidea, in which the respiration is by trachea, and the 

 abdomen is separated from the cephalothorax. 



8._Water bears (Ardisca), which have a vermiform body, 

 with four pairs of rudimentary limbs. 



^,^Fentastomidea, which have a vermiform body, the embryo 

 only with two pairs of rudimentary hmbs. 



Spiders {Aranetdea), an order of the class Arachnida. 



The body of a spider is divided into an unsegmented cephalo- 

 thorax and a swollen abdomen, also unsegmented and attached 

 to the former by a narrow stalk. The cephalothorax is covered 

 above by a plate or carapace, more or less horny, while the abdo- 

 men is generally soft. The whole body is covered with hairs, 



bristles, or tubercles. . 



Attached to the cephalothorax there are four pairs of seven- 

 jointed walking limbs, which are usually long and slender, ending 

 in two claws, and to which one or more claws are sometimes added. 

 Above these are another pair of appendages, the pedipalpi, answer- 

 ing to the maxilla of insects ; their bases act as jaws ; and their 

 palpi are five-jointed, and in the female resemble simple legs, but 

 in the male their terminal joint is pecuUarly modified as a copu- 



latory organ. 



Above the mouth are the first pair of appendages, the falces or 

 chelicerae which consist of two joints and a powerful basal joint 

 grooved on its inner surface, also a claw-shaped terminal joint or 

 fang at the point of which the duct of a poison-gland opens. 

 These fangs, whose office is to catch and kill the prey, are, when 

 not in use, folded back into the groove of the basal joint. 



The basal joint has generally a row of teeth on one or both 

 edges of the groove, and assists in eating, moving usually from 

 side to side. On the first margin of the cephalothorax are usually 

 eight, sometimes six or less simple eyes. The abdomen is always 

 larger or more swollen in the female. On its ventral surface in 



