PRIMATE ALVEOLINGUAL SALIVARY AREA 



123 



the lateral border of the held is occupied by a number of separate 

 small glands sur\-i\dng from the primitive sagittal line A of the left side. 



c 

 C' 



000 0- 



I 



Fig. 2. 



If the entire genetically available field of the alveolingual glandular 

 anlages were imagined spread out in the form of a square containing 

 ten individual anlages each in ten sagittal and coronal lines, it would 

 be theoretically possible to deduce from the one hundred separate 

 glands, through continued development of certain groups and sup- 

 pression of intervening elements, the definite patterns characterizing 

 the various types of adult glandular arrangement in this region, pro- 

 vided the fact were recognized that some of the primitive anlages are 

 destined to develop into conducting canals, while others group together 

 to form the secreting glands. Thus if the series of separate glands 

 shown on the left side of Fig. 3 have genetically resulted from se- 

 lective de\^elopment and differentiation of the corresponding portions 

 of a primitive uniform alveohngual field shown on the right side, this 

 process might be analyzed in the schema given in Fig. 4. Here 

 the chief line of cleavage is at the coronal level F, and it divides the 

 entire complex into main cephalic and caudal groups. The coronal 

 cleavage line F may not be absolutely retained throughout, in which 

 case, for example, the four primitive glandular anlages forming the 



