Dissection of Sheep^s Head. 217 



than the first, is another ganglion ; and lastly, there is one 

 on each nerve strand which crosses the primary bifurcation of 

 the duct, tracing it backwards : the whole forming as it were 

 a second and posterior factor of the submaxillary ganglion, 

 which will be noted later on in connection with the Chorda 

 Tympani, after removal of the jaw. 



Having found the duct and nerve plexus, a stoutish bristle 

 should be passed up the duct, and the fat and connective tissue 

 dissected away from the surface of the gland and adjoining 

 structures : and here again care must be taken between the 

 border of the gland and the occipital condyle, lest a large 

 nerve cord be cut away which runs from the direction of the 

 condyle parallel with the posterior margin of the, ramus and 

 angle of the jaw. 



The submaxillary duct will be seen to run forwards between 

 two muscles : of these, that inserted into the inner posterior 

 border, and angle of the inferior maxilla, is the Internal Ptery- 

 goid muscle, which takes its origin mainly, as its name would 

 imply, from the inferior part of the crest of the Palatine and 

 Pterygoid bones. When acting singly these muscles produce 

 a lateral motion, together they raise the jaw and close the 

 mouth. 



The second and internal of the two muscles is the Digastric*, 

 a long thin muscle that runs alongside the inner edge of the 

 ramus of the maxilla, attached to the inner edge of the 

 horizontal part of the jaw, and to the Paroccipital process : 

 it is so called from its consisting of two fleshy bellies united 

 by an intermediate tendon. In two points its arrangement 

 difiers from that in Man ; first, in that its tendon does not per- 

 forate the Stylohyoid muscle ; and, secondly, in that it does 

 not arise from the digastric groove on the inner side of the 

 mastoid process of the temporal bone ; which would be impos- 



* diQ, twice ; yaaTrip, a belly. 



F F 



