214 Mammalia, 



course of tlie Parotid duct is frequently marked by pigment. 

 By tracing it a sliort distance within the substance of the 

 gland, the component radicles of the main duct will be ap- 

 parent coming in alternately from either side. 



The Nerves and duct should he next cut across about the 

 middle of their course, and reflected together with the sub- 

 cutaneous fat, in order to expose the chief muscle of the face, 

 which has been incidentally mentioned above, viz., the 

 Masseter Muscle. This muscle consists of several layers, in- 

 tersected by tendinous bands, enclosed in aponeurosis. A 

 superficial portion is marked out, arising from a tuberosity on 

 the superior maxilla by a thick tendon, its fibres passing 

 obliquely downwards and backwards, to be inserted into the 

 outer surface of the posterior border and angle of the inferior 

 maxilla. A middle portion of the muscle lies rather deeper, 

 and arising from the ridge of the malar bone and anterior half 

 of the Zygomatic arch, its fibres also passing to the angle 

 posterior external surface of the ramus. A third and 

 deepest portion, rising from beneath the Zygomatic process, 

 is inserted into the external surface of the ramus, just below 

 the Sigmoid notch, between the condyle and the Coronoid 

 process. 



One other muscle may be noted in close relation with a 

 nerve, viz., the Levator lahii superioris alseque nasi, which is 

 situated on the side of the face, arising close to the point of 

 origin of the most superficial part of the Masseter, and ex- 

 tending forwards to the upper lip. By reflecting this muscle 

 from its upper side, and cleaning away the subjacent fat by 

 longitudinal scraping, the anterior termination of the infra- 

 orbital nerves will be disclosed. It will be remembered that 

 from the Gasserian ganglion, near the commencement of the 

 Fifth Nerve, three large branches proceed : the Ophthalmic, 

 Superior Maxillary, and Inferior Maxillary. Of these the 

 two first are purely sensory ; at the present point in the dis- 



