122 PRIMATE ALVEOLINGUAL SALIVARY AREA 



and the topographical relations of the oral cavity and its environment 

 exert during development on the ultimate disposition and arrangement 

 of the individual salivarj' components. His results suggest that' this 

 influence may be one of the strongest factors responsible for the initial 

 selection of special areas of a common primitive glandiferous field for 

 more individual and higher development as distinct and independent 

 major glands. (Cf. Schulte, Parts VI and VIII.) 



I. Genetic Theory of Primate Alveolingual Salivary 

 Development 



The ontogenetic conditions just outUned, and the additional e\i- 

 dence supplied by the adult sahvary structures of this area in some of 

 the lower vertebrates, make it possible to conceive the entire alveo- 

 hngual gutter of the oral floor as the site of a group of primitive equiva- 

 lent individual glandular anlages distributed uniformh- over its entire 

 extent. This common potential field may be assumed to be capable 

 of specific dift'erentiation into distinct separate districts of ontogenetic 

 salivary activity. This tendency to rearrange the indi\'idual com- 

 ponents of the glandiferous area into specialized groups may manifest 

 itself along, — 



I Coronal lines of segmentation. 

 II Sagittal lines of segmentation. 

 Ill Lines which are formed by combinations between sagittal and 

 coronal segmentation. 



Thus if the left side (I) of Fig. i represents the uniform diffuse de- 

 velopment of separate glands in the alveoUngual gutter, these ele- 

 ments can be arranged into the three cephalocaudad groups, A,B,C, 

 shown on the right side of the same figure (11) by the coronal lines 

 of segmentation indicated at a and h, along which suppression of 

 glandular formation occurs. The left side of Fig. 2 (III) shows the 

 rearrangement of the same elements into the lateromesal divisions, 

 A,B,C, separated by sagittal lines of segmentation a and h. 



On the right side of the same Fig. 2 (IV) a combination of sagittal 

 and coronal cUxision has selected certain of the elements into a com- 

 pound gland whose cephahc elements unite into a common duct, while 



