ALIMENTARY CANAL AND ITS APPENDAGES 309 



D 



. 226. DIAGRAM OF THE ORAL CAVITY AND PHARYNX IN A FISH (A), 

 AX AMPHIBIAN (B), A REPTILE (C), AND MAN (D). 



Ch, internal nostril ; D, alimentary canal ; K, gill-slits ; L, lung ; N, external 

 nostril ; O, oesophagus ; T 7 , trachea ; the arrow marked A indicates the 

 respiratory passage, that marked B the nutritive passage ; f, the point where 

 the two passages cross one another. 



