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 Zegenaria domestica and Agelena labyrinthica, 
these two caeca fuse together and form a ring above the 
Fic, 236.—Semi-diagrammatic view of a Spider (petra diademata), to show internal 
organisation. After Warburton. 
1. Mouth. 11. Dorsal vessel or heart, with lateral 
2. Suctorial stomach. ostia. 
3. Liver ducts. 12. Lung-sac. 
4. Malpighian tube. 13. Ovary. 
5. Stercoral pocket. 14. Acinate and pyriform silk-glands. 
6. Anus. 15. Tubuliform silk-gland. 
7. Dorsal muscle of stomach. 16. Ampulliform silk-gland. 
8. Lower portion of stomach. 17. Aggregate or dendriform silk-gland. 
9. Cerebral ganglion, giving off nerves 18. Spinnerets or mammillae. 
to the eyes. 19. Falx (distal joint of chelicera), 
10. Thoracie ganglion, giving off nerves 20. Poison gland. 
to the legs. 21. Hye. 
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 Lpeira 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 
