412 



ZOOLOGY 



true stomach, this gives off a remarkable series of caeca, two of 

 which pass forward and end blindly near the poison glands. 

 In some species, as Tegenaria domestiea and Agelena Idbyrinthica, 

 these two caeca fuse together and form a ring above the 



Fig. 236. — Semi-diagrammatic view of a Spider (Epeira diademata), to show internal 

 organisation. After Warburton. 



cerebral ganglion. The stomach gives off four pairs of lateral 

 caeca, each of these passes into the base of a leg and then turns 

 back again and ends blindly between the ventral nerve mass 

 and the ventral integument. These caeca in Epeira diademata 

 end blindly, but in some species they fuse together and form a 

 common cavity. Thus the stomach and its caeca may in the 

 Araneida form a very complex system of anastomosing loops, 

 some of which project a short way into the legs. 



From the stomach the intestine passes backward; it tra- 

 verses the constricted stalk between the cephalothorax and 

 abdomen, and then takes a curved course lying beneath the 

 heart, and finally opens into a large rectum. The intestine 

 gives off numerous tubules which bifurcate into a large number 

 of small ducts which ultimately end blindly ; these constitute 



