33° 



PHYSIOLOGY AND MORPHOLOGY OF ANIMALS. 



this regard, as in so many others, may be regarded as a 

 generalized mean. The intestinal canal is shorter in car- 

 nivores and much longer in herbivores than in man. It 

 may be well, however, to mention one or two interesting 

 points. The cfecum, which in man is but a slight en- 

 largement of the blind end of the large intestine (see 

 Fig. 204), is greatly enlarged in the horse, and in the 



Fig. 2ii.— The alimentary canal of a rat : st, stomach ; ca, caecum. 

 (From Owen.) 



rat is indeed a sort of second stomach as big as the true 

 stomach (Fig. 211). The most interesting thing in this 

 connection is the origin of the strange wormlike appen- 

 dix. It is probably the remnant of the shriveling of the 

 extreme end of a much longer caecum. It is an example 

 of a useless remnant of a once useful organ. 



