654 DEVELOPMENT OF THE ALIMENTARY CANAL, ETC. 



low. Fissure of the palate is caused by a deficiency, more or less 

 complete, of one of the horizontal maxillary plates. It is accord- 

 ingly situated a little on one side of the median line, and is fre- 

 quently associated with hare-lip and fissure of the upper jaw. The 

 fissures of the palate and of the lip are very often continuous with 

 each other. 



The anterior and posterior pillars of the fauces are incomplete 

 vertical partitions, which grow from the sides of the oral cavity, 

 and tend to separate, by a slight constriction, the cavity of the 

 mouth from that of the pharynx. 



When all the above changes are accomplished, the pharynx, 

 oesophagus, mouth, nares, and fauces, with their various projections 

 and divisions, have been successively formed ; and the development 

 of the upper part of the alimentary canal is then complete. 



