6 THE ANATOMY OF THE ADULT HUMAN SALIVARY GLANDS 



unfolding is ectomasseleric. These elements represent the reduced 

 homologues of the orbital series of glands, which in some of the lower 

 mammalia (Carnivora) reach a relatively high degree of development. 



The superior and inferior alveobuccal and alveolabial sulci, which 

 in certain of the lower mammalia yield distinct groups of molar and 

 labial glands, are in the adult human the site of more or less reduced 

 glandular development {alveobuccal or molar glands). Their for- 

 ward extension, however, into the lips is responsible for the develop- 

 ment of the distinct masses of separate superior and inferior labial 

 glands, especially pronounced in the negroid races and largely re- 

 sponsible for the characteristic bulging and protruding lips of these 

 human racial tjpes. 



No attempt has been made in the following pages to repeat the 

 stereotyped descriptions of the human salivary glands, current in 

 the general anatomical text-books. Only those conditions which seem 

 to me worthy of special mention have been treated in any detail. 



[Many new and important facts in reference to the parotid gland have recently 

 been described by Mr. Parsons,* and the topographical anatomy of the human 

 salivary glands has been treated by Professor Symington, to whose admirable 

 paper the reader is referred. f] 



On the other hand I have endeavored to furnish a series of illus- 

 trations of the adult human saUvary apparatus which, I hope, will 

 prove of some service. 



They represent accurately the actual conditions encountered in 

 a large series of carefully injected and prepared subjects. I have 

 been impressed, in the prosecution of this portion of the general 

 research, with the inaccuracy and incompleteness of the illustrations 

 which, especially in the alveohngual district, accompany the reading 

 matter of the majority of accepted anatomical text-books. They 

 seem to have been handed down, unchanged, or in some cases further 

 obscured by reduction in the reproduction, from the earhest decades 

 of descriptive anatomical knowledge. Much of the uncertainty 

 which reveals itself, both in the descriptions of the individual glands 

 and in the accompanying illustrations, is due to the fact that, without 

 injection of the individual major glands, it is practically impossible 



* On the form of the parotid gland. Jour, of Anal. 6* Phys. April, igii. 



t The topographical anatomy of the salivary glands. Jour. Anal, fir Phys., Vol. xlvi. 



