Dissection of Common Rat. 207 



now with the scissors make the two following cuts : one from 

 near the angle of the mouth to the anterior corner of the eye, 

 and another from the front of the ear, in a direction above 

 the level of the eye ; and join these two cuts along the lower 

 margin of the eye. This piece of skin should be dissected 

 away, and also the underlying superficial muscles and fascia. 



There will then be apparent the outer margin of the 

 almost conjoined Hybernating and Submaxillary Glands, 

 which were reflected in a previous dissection ; and between 

 them and the Ear the Parotid Gland. From the lower 

 margin of the Parotid Gland, a duct will be seen pass- 

 ing to the angle of the mouth : this is the duct of the Parotid 

 Steno's duct. The muscle over which it passes on a level 

 with the teeth of the lower jaw, is the Masseter muscle. 

 Between the upper margin of the Parotid Gland and the Eye, 

 a second perfectly distinct gland of a darker hue (in the 

 fresh state) than the Parotid may be made out, from which 

 a rather broad duct proceeds to enter the orbit ; this gland 

 is the facial, extra- orbitally placed portion of the Lachry- 

 mal Gland. The orbital portion of this gland may be brought 

 to view, together with the Harderian Gland, by gently press- 

 ing the eyeball upwards and forwards. 



Dissection of Anterior Factors of Descending Cava. 

 The Student should now clean and separate the three 

 glands just seen from one another, turning the Submaxillary 

 downwards, the Lachrymal up over the Ear, and leaving 

 the Parotid in situ. By dissecting in the substance of the 

 Parotid Gland, the Student will find the vessels from the face 

 uniting to form the commencement of the temporal vein, 

 which reaches from the Zygoma on which it rests to the 

 angle of the jaw, and is succeeded by the external jugular 

 vein. He should then trace this back along its course, which 

 is marked by a line from the angle of the lower jaw to the 

 clavicle, crossing the sterno-mastoid muscle ; and will note 



