202 



STRUCTURE OF THE VERTEBRATES 



Availed small intestine and a thick-walled large intestine or colon. 

 The small intestine is not continuous with the large, but enters 

 it at approximately a right angle some distance from its anterior, 

 blind end. This blind pouch, the caecum, is large in the herbi- 

 vores and a functional part of the intestine, for its bacterial con- 



Small 



intestine-^ 



Fig. 116. Caecum of a Rabbit. Digestive caeca are found in many groups 

 of vertebrates. In the mammals it usually is found at the ileo-colic junc- 

 ture. In some herbivores the caecum contains cehulose-breaking bacteria. 



Small 

 intestine 



'Vermiform 

 appendix 



A. 2 months Foetus 



ermiform 

 apperidix 



B. Newborn 



C. 4 Years 



Fig. 117. Development of the Vermiform Appendix in Man. The digestive 

 caecum degenerates in man, and is loft as a small appendix in the adult. 



(After Kollman). 



tent assists in breaking down the cellulose of plants. The caecum 

 of the human is short and terminated by a small vermiform ap- 

 pendage. The evidence from embryology and the comparative 

 anatomy of the primates indicates that the appendix is the ves- 

 tigial remains of a once large caecum. 



The rectum is the terminal enlarged portion of the intestine, 



