34(3 ORGANS OF DIGESTION. 



pecially in the contracted state of the trunk. In the nereides 

 there is generally an exsertile broad proboscis (Fig. 14. 1. a.) 

 at the anterior end of the head, numerous lateral jaws which 

 are remarkable for their frequent unsymmetrical number 

 and development on the two sides of the mouth, a distinct 

 gastric cavity furnished with longitudinal internal folds and 

 with numerous sharp horny teeth, and an elongated intestine 

 furnished throughout the greater part of its extent with 

 lateral cceca, or biliary follicles, as in most of the higher 

 annelides. 



The digestive organs of the entomoid classes, like most 

 of their other organic systems, are characterized by a more 

 elevated grade of the same plan of development followed 

 throughout the helminthoid articulata ; and by the higher 

 condition of their organs of sense and locomotion, they are 

 better enabled to select their food, and to overcome more 

 highly organized prey. 



X. Myriapoda. In the long, equally developed, vermi- 

 form bodies of the myriapods, we still find an imperfect 

 condition of the masticating organs, and the most simple 

 helminthoid form of the alimentary canal, which accord 

 with the characters of inferiority marked in their other 

 organs, and with the cruel and carnivorous propensities 

 these animals display in the living state. The masticating 

 organs of the scolopendrae (Fig. 15), consist of a small pair 

 of mandibles and a similar pair of maxillae, which are fol- 

 lowed by two pairs of larger jointed organs formed by the 

 metamorphosis of the two first pairs of feet into masticatory 

 jaws. The mouth is furnished with an upper and lower 

 lip, and with long, simple, salivary follicles, like those of in- 

 sects, enlarged at their closed extremities. The alimentary 

 canal, like that of most of the higher annelides, passes 

 through the whole longitudinal axis of the body, with thin 

 membranous parietes, with little appearance of gastric en- 

 largements, and without convolutions. The contracted oeso- 

 phagus opens into a wider lengthened gastric cavity with 

 thin parietes, and this elongated membranous stomach is 

 succeeded, as in serpents, by a narrow small intestine which 

 terminates in a perceptibly wider colon : so that the alimen- 

 tary canal here presents affinities both to that of the higher 

 forms of worms, and to that of the vermiform ophidian rep- 



