8 Lkach, The Myology of ihe Bell-Mag/ne. f ,^Ti 



(_ I SI July 



i6. The biv enter maxillce. 



17. The entotympanicus. 



18. The pterygoideus inter nus. 



19. The pterygoideus extermis. 



20. The digastric. 



14. The temporal [11], [12]. — This strong muscle, assisting in 

 closing the jaws, arises fleshy from the temporal fossa which it 

 fills. A few fibres arise from the neighbouring parts of the skull 

 in front, the sphenotic process, and the wall of the orbit. The 

 fibres converge and pass downward and forward to be inserted 

 in the coronoid process upon the upper margin of the mandible. 

 Shufeldt found that the fibres joined those of the masseter (15), 

 in the American Raven. Such a union is not conspicuous in the 

 Strepera, and is restricted to, at most, but a few fibres. 



15. The masseter [12] assists the last-named muscle ; it has its 

 broad end below and its narrow end uppermost, arises below the 

 temporal (14) from the bony ridge above the entrance to the ear, 

 and passes downward and forward, spreading out as it goes. In 

 passing, it makes a tendinous attachment to the upper margin 

 of the lower jaw, and is inserted fleshy about the vacuity in the 

 mandible. A smaller part is inserted tendinously on a small 

 tubercle on the mandible just posterior to the main bulk of the 

 muscles. 



16. The hiventer maxillce [5], [11], [12], [14a], a mass of muscle, 

 covers the articulation of the jaws posteriorly. It rises from a 

 ridge and a neighbouring depression behind the ear, and is 

 inserted superficially about the end and angle of the lower jaw. 



17. The entotympanicus [13] is an interesting muscle, small and 

 spindle-shaped. It arises fleshy from the side of the basisphenoid 

 and the rostrum. It passes across, splitting into two — a fleshy 

 division inserted fleshy on the quadrate, and an anterior division 

 becoming tendinous, and inserted on a tubercle near the distal 

 end of the posterior aspect of the pterygoid bone. 



18. The pterygoideus internus [14] arises on the upper side of 

 the palatine as a fleshy mass on each side. It passes backwards, 

 outwards, and downwards, to be inserted about the angle of the 

 lower jaw. The fleshy mass is tendinous on the inner exposed 

 side. 



19. The pterygoideus externus [5], [14J crosses the pterygoideus 

 internus (18). It arises fleshy from the quadrate bone, runs 

 forward and downward, to be inserted about the vacuity in the 

 mandible on the inner side. It fills the fossa made by the peculiar 

 posterior processes of the palatines in these Austro-coraces. 

 Through the vacuity its fibres may be in contact with those of 

 the masseter. 



20. The digastric [5] [12] is a thin semi-transparent muscle, 

 difficult to trace exactly. It arises from the base of the skull, 

 on the basi temporal, about opposite the angle of the lower jaw. 



