CHAPTER XII 

 LEPUS CUNICULUS (continued) 



Digestive System Respiratory System Circulatory System The Mammalian 

 Heart Urogenital System Ductless Glands. 



Digestive System. 



The digestive system is composed of the alimentary 

 canal and its related glands, and in the rabbit consists of the same 

 main parts as in Rana. 



The mouth is bordered by very freely movable lips of which the 

 upper, as has been noted, is cleft. The buccal cavity is narrow and 

 long as compared with the frog. Within the jaws are the teeth 

 whose form and distribution we have already considered. The 

 roof of the buccal cavity is composed of a mass of tissue termed the 

 palate. The nasal cavities, instead of communicating by the internal 

 nares with the front end of the buccal cavity, pass into long passages, 

 the narial canals, which open by the nares back in the pharyngeal 

 region, and it is the palate that constitutes the partition separating 

 the buccal cavity from these canals. The front part of this roof 

 contains osseous structures, namely, the palatine processes of the 

 pre-maxillae, the maxillae and the palatine bone ; it is consequently 

 termed the hard palate. The hinder part, on the contrary, is com- 

 posed entirely of membrane and connective tissue and so is designated 

 the soft palate. Right at the front end of the palate are a pair of 

 grooves terminating in small apertures, just behind the posterior 

 incisors, which lead into the naso-palatine canals, and these form a 

 means of communication between the anterior portions of the 

 nasal chambers and the buccal cavity. In the sides of the hinder 

 end of the soft palate are two small pits, the tonsils. The floor of 

 the mouth cavity is mainly occupied by the long prominent muscular 

 tongue, which unlike that in Rana is attached posteriorly and free 

 in front. It is covered with tiny white spots that mark the position 

 of the taste papillae. On the sides of the posterior end of the tongue, 

 level with the last molar teeth, are a pair of oval patches crossed by 

 parallel ridges and termed the papillae foliatae. Just above and 



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