42 THE STRUCTURE OF THE FOWL 



part carries a transverse row of simple, large, 

 and horny papillae with apices directed towards 

 the pharynx.^ The intrinsic lingual muscles 

 are rudimentary, as would be expected from 

 the unyielding nature of the mucous mem- 

 brane ; but the muscles connected with the 

 hyoid bone are well developed. 



The hard palate (Fig. 10), which forms the 

 roof of the mouth, presents a long, narrow, 

 median slit, communicating with the nasal 

 cavities, and is beset with transverse rows 

 of horny, conical papillae with apices directed 

 backwards. 



As already stated, the pharynx is directly 

 continuous with the mouth. In the middle of 

 its dorsal wall is the narrow slit-like opening 

 common to the two auditive tubes of Eustachius 

 by which air gains access to the drum of the 

 ear and the interior of the spongy bones of the 

 skull. Immediately behind this opening is a 

 transverse row of conical papillae. 



The floor, or ventral wall, of the pharynx pre- 

 sents the narrow orifice leading into the larynx, 

 and, behind this, a double row of papillae. 



The mucous membrane lining the whole of 



^ A study of the development of the tongue leads to the con- 

 clusion that its true posterior limit is behind this row of papillae. 



