246 Anatomy of the Rabbit. 



In the oral cavity: 



(a) The hard palate (palatum 4urum) forms the anterior 

 • portion of the roof; its mucous membrane is thrown into a 



series of transverse ridges. 



(b) The soft palate (palatum molle) is the thin, narrow, 

 posterior, membranous portion of the roof. It is very long 

 in the rabbit, extending frorn the bony palatine bridge 

 backward to a point above the laryngeal aperture, where it 

 ends with a concave free margin. 



(c) The nasopalatine or incisive ducts (dd. nasopalatini) 

 open by minute apertures immediately behind the small 

 iacisors. They connect the anterior portion of the nasal 

 cavity with the mouth. 



(d) The tongue (lingua) projects upward and forward from its 

 basal attachments on the hyoid into the floor of the mouth. 

 Its connection with the latter is extended forward in the 

 middle line by a vertical membranous fold, the frenulum 

 linguae. Its dorsal surface is divided into a posterior 

 smooth and hard portion, and an anterior softer and rougher 

 portion, occupied by fine low elevations, the fungiform 

 papillae (papillae fungiformes) . At the posterior end of the 

 smooth portion there is on either side a minute spherical 

 elevation, set low into the mucous membrane, the vallate 

 papilla (papilla vallata), and in a more lateral and anterior 

 position an oval area, the papilla foliata, the surface of 

 which is marked by fine parallel ridges. Both vallate 

 and foliate papillae are occupied by microscopic taste-buds. 



In the pharynx: 



(a) The tonsil (tonsilla) appears as a rounded mass of lymph 

 follicles lying on the anterior wall of a deep lateral depres- 

 sion, the tonsillar sinus (sinus tonsillaris). The vertical 

 slit-like aperture of the sinus is bounded by . low anterior 

 and posterior folds. 



(b) The epiglottis, a valve-like fold guarding the entrance 

 to the larynx, projects upward from the floor into the 

 pharyngeal cavity. 



(c) By removing the posterior portion of the soft palate, the 

 connection of the nasopharynx with the nasal fossae will be 



