334 



COMPARATIVE PHYSIOLOGY. 



sel is small or liquid is swallowed, it is rapidly propelled on- 

 ward by the tongue, the oesophagus and pharynx being largely 

 passive at the time, though contracting sjowly afterward; at 



\ 



Pis. 274.— Cavities of mouth and pharynx, etc., in man (after Sappey). Section, in 

 median line, of face and superior portion of necls, designed to show the mouth in 

 its relations to the nasal fossge, pharynx, and larynx: 1, sphenoidal sinuses; 2, in- 

 ternal orifice of Eustachian tube; 3, palatine arch; 4, velum pendulum palati; 5, 

 anterior pillar of soft palate; 6, posterior pillar of soft palate; 7, tonsil; 8, lingual 

 portion of cavity of pharynx; 9, epiglottis; 10, section of hyoid bone; 11, laryn- 

 geal portion of cavity of pharynx; 13, cavity of larynx. 



the same time the larynx as a whole is raised, the epiglottis 

 pressed down, chiefly by the meeting of the tongue and itself, 

 while its cushion lies over the rima glottidis, which is closed 

 or all but closed by the action of the sphincter muscles of the 

 larynx, so that the food passes over and by this avenue of life, 

 not only closed but covered by the glottic lid. The latter is 

 not so essential as might be supposed, for persons in whom it 



