A Coiiliil)uliiiii to (lie Anatomy of Siren laicrtiiia. 671 



part of Henle's muscle of this name, I feel uo hesitancy in calling 

 them such, for the name applies exactly, while the dilatator of Hknle 

 referred to the system of pharyngeal constrictors. The dilatatores form 

 the inner half of the circumlaryngeal band and arise from a median 

 raphe between them. Their insertion corresponds in every points with 

 that of the constrictores, being, of cause, on the opposite side of the 

 same structures. 



Although I have not been able to find the innervation of the 

 dilatatores, there can be no doubt that they receive their supply from 

 the same source as the constrictores. 



Note. In a dissection made since the above went to press, 

 I was able to demonstrate a fine lateral twig, which branches from 

 the nerve supplying the constrictors, curves around the larynx and 

 supplies the dilatators. 



For the mechanism of this system of intrinsic muscles, see the 

 section on the larynx. 



16. Pterygo-maxillaris (figs. 1, 4, 5 Pt m.). 



Preparation. This muscle is subcutaneous at its insertion, but 

 at its origin much deeper than all the other muscles. Its preparation, 

 therefore, nmst be left to the last. After the removal of the hyoid 

 apparatus, its entire inferior surface becomes exposed. Ramus pala- 

 tinus facialis runs along the edge of the parasphenoid, near the origin 

 of this muscle, while Ramus alveolaris issues from beneath it at its 

 anterior border. The muscle should be completely cut away from its 

 insertion and reflected, exposing somewhat more of the two nerves 

 first mentioned. 



Origin. It arises from a sharp ridge of the skull, between the 

 articulation of the mandible and the antorbital process, as well as 

 from the surface of the bones superior to this line, the parasphenoid 

 and ethmoid. 



Insertion. This is eff'ected by direct fibres to the inferior angle 

 of the mandible, also by two or three tendons to a ridge which runs 

 transversely across the Ijone from that point. 



Innervation. I liave been able to demonstrate the innervation 

 of this muscle only by serial sections and feel quite sure that I have 

 found only a small and unimportant branch. The one I have found is 

 a small branch issuing from the Ramus maxillae inferioris immediately 

 after its exit from the cranium. This branch runs between temporalis 

 and this muscle, giving branches to both. 



