128 Journal of Comparative Neurology 



The olfactory nerves in man enter the nasal epithelium 

 through some twenty openings in the bony arch and then branch 

 into a perfect meshwork of fibrillae, their extremities reaching 

 to unite with the minute cells of the epithelial layer. Other 

 accessory nerve-bundles which which supply the olfactory organs 

 are, a branch of the ophthalmic (V), filaments from the anterior 

 dental branch of the superior maxillary, the vidian, naso-palat- 

 ine, descending anterior palatine, and nasal branch of Meckel's 

 ganglion. 



8. Function of Jacobsori s Organ. Notice that among ani- 

 mals which live more or less on, or near, or burrow in the earth, 

 such as ruminants, rodents, lizards, snakes, amphibians, etc., 

 Jacobsori s organ is more or less developed, while the nose is 

 simple and comparatively undeveloped ; while among animals 

 that live entirely or mostly in the water, and in general among 

 those animals who do not bring the nose to the ground, and do 

 not depend upon the sense of smell in the search for food, as in 

 man, birds, fishes, crocodiles, chelonia, etc., we find Jacobson's 

 organ undeveloped or only rudimentary, while the nose proper 

 is often quite complicated in its structure. 



Again, glands seem abundant in water-livers, and more 

 scarce in land-livers. Compare the difference even between the 

 groups of Reptilia where you would not expect so marked a 

 difference. Chelonia and Crocodilia are well supplied, while 

 there is a comparative paucity of glands in Lacertilia and Ophid- 

 ia. The Junction of Jacobsoris organ is to determine directions, 

 perhaps. Others suggest that it may consist in bringing the 

 food taken into the mouth under the direct control of the olfac- 

 tory nerve. In Reptilia for example, the function of Jacobson's 

 organ seems to be to perceive odors of food during mastication. 

 In man these functions, whatever they are, are evidently assumed 

 by the turbinal convolutions. 



//. Cartilaginous Investment. 



Born and Solger have given good accounts of the ana- 

 tomical relationships of the olfactory organ, in its rela- 

 tion to the bones of the cranium, the skeletal parts of the 



