40 LHE THORACIC VISCERA, (BOUCCALY CAVITY, 
between the lower turbinate and the palate, while the 
olfactory passages proper le between the upper 
ethmoidal turbinates. 
a. THE SCHNEIDERIAN MEMBRANE is the mucous 
membrane covering the upper turbinates. It is usually 
of a darker.color than the rest of the nasal mucous 
membrane, and contains the end organs or cells of 
the olfactory nerve-fibres. 
. 5. The Salivary Glands. 
LDissect on the side not previously used. No especial 
directions are required. 
a. THE PAROTID GLAND Is not very prominent in the 
dog. It lies posterior to and somewhat in front of 
the ear, and forms a somewhat indefinite pinkish mass. 
b. Stenson’s Duct, the duct of the parotid, arises 
from the ventral margin of the gland, runs across 
the middle of the masseter muscle, bends inward at 
the border of the muscle, and opens into the mouth by 
a small aperture on the inside of the cheek opposite 
the posterior portion of the last premolar of the 
maxilla. Insert a probe into the duct and demon- 
strate the opening into the mouth. 
c. THE SUB-MAXILLARY GLAND forms on each side 
a compact mass lying just posterior to the angle of 
the mandible and concealed by connective tissue, 
which must be cleared away. 
d. Wuarton’s Duct. The duct of the sub-maxil- 
liary will be exposed best if the attachment of the 
digastric (see page 65) to the mandible is cut, and 
this muscle reflected backward as far as possible. If 
the thin sheet of muscle (mylo-hyoid) lying in the 
floor of the mouth is now carefully cut the duct will be 
exposed, and can be traced back to the gland and for- 
ward to its opening upon the floor of the mouth. 
