OLFACTORY ORGANS. 



I 97 



Stenson's gland; in other mammals, so far as known, its duct becomes 

 cut off from the nasal cavity and opens into the naso-palatal canal. Its 

 medial wall is covered with sensory epithelium, supplied by a branch 

 of the olfactory nerve. In the primates the organ is more or less de- 

 generate in the adult. 



There are two kinds of glands in the nasal cavity, the smaller and 

 scattered Bowman's glands and the larger Stenson's gland lying in 

 the lateral ventral wall and opening into the vestibule. There are 

 usually several sinuses in the bones of the skull, connected with the 



FIG. 203. Lateral wall of nasal cavity of man, after Corning, eg, crista galli; ci, cm, 

 cs, inferior, middle and superior conchae;//w, foramen palatinum majus;/^, sphenopala- 

 tine foramen; ic y incisive canal; asm, opening of maxillary sinus; sf, frontal sinus; ss, 

 sphenoidal sinus. 



nasal cavities by foramina. Chief of these are the maxillary sinuses 

 (antra of Highmore), the frontal and sphenoidal sinuses in the 



corresponding bones, the relations of which may be seen in fig. 203. 

 Others may occur in other bones of the face. 



Mammals are characterized by an external fleshy nose, supported 

 by the nasal bones and by cartilages, developed in part from the eth- 

 moid cartilage of the embryo, in part from paired cartilages, a new 

 acquisition of the mammals. Beyond these skeletal parts is the fleshy 

 portion which may form a proboscis of considerable size (swine, 

 elephant shrew, elephant). 



