302 DISSECTION OF THE EABBIT 



a. The orifices of the Eustachian tubes are a pair of 



oval apertures at the sides of the roof of the 

 chamber, about the middle of its length. 



Pass a seeker backwards and outwards, along one of the 

 Eustachian tubes, into the tympanic cavity. 



b. The organs of Jacobson are a pair of tubular bodies 



enclosed in cartilage, and lying in the floor of 

 the anterior part of the nasal cavity. Each com- 

 municates in front with the mouth by the naso- 

 palatine canal, and ■with the nostril by a more 

 dorsally placed opening. 



Gut away with hone-forceps the left side of the nasal 

 chamber, so as to lay open the cavity completely. Remove the 

 mesethmoid cartilage, and note the arrangement of the tur- 

 binal bones, and the relations of Jacobson' s organs. 



6. The salivary glands are large and paired. 

 Dissect from the left side. 



a. The parotid gland, the largest of the saUvary 



glands, is a soft pinkish mass lying in front of 

 and below the external auditory meatus, between 

 this and the hinder edge of the mandible. 



The duct, Stenson's duct, leaves the gland at 

 its anterior border, and runs forwards just beneath 

 the skin, parallel to and about a quarter of an 

 inch below the zygomatic arch. It opens into 

 the mouth by a small aperture on the inner side 

 of the cheek, opposite the second upper premolar 

 tooth. 



b. The in&a-orbital gland is an irregular lobulated 



mass, about three-quarters of an inch long, lying 

 below and in front of the eye, partly above the 

 zygomatic arch and partly hidden by it. 



The duct runs downwards to open into the 

 mouth. 



c. The submaxillary gland is a compact, reddish, 



ovoidal mass, lying close to its fellow between 



