LESSON 43.] NUTRITION IN THE AEACHNIDA. 



153 



FIG. 249. 



The short, strong upper jaws (Fig. 249) are provided with sharp 

 pointed, slightly curved teeth (6), which are hollow, like the poison 

 fang of a serpent, and for the same pur- 

 pose the transmission of the saliva. 



The instant a Spider bites a fly, or 

 another individual of its own species, 

 the saliva is poured out abundantly 

 through the cavity of the tooth simul- 

 taneously with its insertion. 



As a consequence, the victim is 

 poisoned, the body swells considerably, 

 and it dies immediately. 



Now commences the process of feed- 

 ing, which simply consists in sucking up the juices of the slain. 



To assist this process, the base of the teeth (a) is provided with 

 a double coronet of short, strong, pointed spines, upon which an 

 insect is literally impaled, whilst the killing and feeding progresses. 

 At the lower part of the jaws (d) two large cavities are seen, out 

 of which the muscles were extracted. 



The under jaws (maxillge) are shown at a (Fig. 250), in the form 



FIG. 250. 



Upper jaws of the Spider. 



Under jaws, Spider. 



of short strong organs, whose function it is to hold the insect, whilst 

 the upper jaws kill it, and suck up its juices. 



This operation is greatly assisted by the long, strong, five-jointed 

 feelers (b, 5), each of which terminates in a short hooked process (c). 

 Surely no better form of apparatus could have been contrived to 

 meet the special and peculiar requirement of a Spider. 



680. In the domestic spider, the oesophagus (a, Fig. 251) passes 

 beneath the brain, and expands into a stomach almost as broad as 

 the sternum, which sends off a large coecal process into the base of 

 the maxillary palpi (6), and of each thoracic leg ten coecal appen- 

 dages in all. A shorter diverticulum (a turning) is continued 

 from the upper part of the stomach (d). Where the intestine 



