PRIMATE ALVEOLINGUAL SALIVARY AREA 139 



We are hence confronted with a series of adult human variants which 

 practically include, within their own scope, the entire range of the 

 various types established by the detailed examination of adult in- 

 dividuals belonging to the various genera and species of the primate 

 order of mammals. 



It follows that observed types of salivary organization in individuals 

 have the gambler's value of a concrete instance of the number of points 

 shown by the cast dice. Still the cube of the dice must show on each 

 face all of the available points, and if, in a long-continued succession 

 of throws, the same results appear, then it is fair to assume that they 

 are weighted. In other words, the organization of the alveolingual 

 saUvary area obtaining in a majority of individuals of any particular 

 group represents the product of all possible combinations plus a deter- 

 mining factor. This establishes an average phylogenetic type for the 

 group as a whole acquired during its period of definite differentiation. 

 This view does not hmit individuals of such a group to a constant and 

 necessary conformity with the prevalent and standard type of saUvary 

 organization. It does, on the other hand, imply that departures 

 from this standard, common to the group as a whole, have attained 

 the value of phylogenetic, in contradistinction to ontogenetic, 

 variants. 



In analyzing the adult primate salivary glands of the alveolingual 

 area including those of man, in the light of the preceding genetic con- 

 siderations, all the conditions above reported may be grouped under 

 the following main headings : — 



I. Primate forms in which all three of the typical sagittal alveo- 

 lingual lines of potential salivary development are utilized and 

 in which the adult individual consequently possesses the lateral or 

 lesser sublingual group of individual glands, the intermediate or 

 greater sublingual gland and duct, and the medial or submaxillary 

 gland and duct (with or without accessory and secondary glandular 

 elements). 



This general group is divided naturally into the following sub- 

 sections : — 



A. Forms in which the submaxillary and greater subhngual glands 

 carry their respective ducts to separate and distinct parafrenular 

 orifices without producing accessory or secondary derivatives of the 



