The Structure mid Habits of Spiders. 21 



the thorax, and fastened between the legs on 

 each side at gg. When these muscles contract, 

 the top and bottom of the sucking-stomach are 

 drawn apart, and whatever is in the oesophagus 

 sucked in. By this pumping motion the spider 

 is supposed to take liquid food from the mouth, 

 and drive it backward into the abdomen. Just 

 behind the sucking-stomach, the intestine gives 

 off two branches, c e, which extend forward 

 around the stomach muscle, and meet over the 

 mouth. Each of these branches gives off on 

 the outer side four smaller branches, m in m m, 

 which extend downward, — one in front of each 

 leg, — and unite on the under side of the 

 thorax. 



The intestine, o, continues backward through 

 the abdomen to the anus, in the little knob 

 behind the spinnerete. The brown mass which 

 surrounds the intestine, and fills the abdomen 

 above it, is supposed to be a secreting-organ 

 discharging into the intestine at several points. 



HEART. 



Over the intestine, and parallel with it, is the 

 heart, /, a muscular tube, with openings along 



