REPORT ON THE SPHENISCID.'E. 



133 



orbital process of the quadrate bone. Its fibres pass obliquely downwards and outwards, 

 and are inserted into the upper border of the ramus of the lower jaw, immediately in front 

 of the articular surface of that bone. 



Action. — This muscle co-operates with the temporal and orbito-maxillary muscles in 

 raising the lower jaw and closing the mouth. 



Relations. — It is concealed on the outer side by both the temporal and orbito- 

 maxillary muscles. 



Nerve supj^ly (?) 



Remarks. — The quadrato-maxillaris apparently corresponds to the quadrato- 

 pterygoidien of Gervais and Alix. I failed, however, to recognise the insertion of any 

 portion of its fibres into the pterygoid bone, as described by these authors. 



6. Levator quadrati. 



Augenhdhlengelenkheinmuskel, Wiedemann, p. 74. 



Augenhdhlen-Quadratknochen-Muskel, Tiedemann, p. 389, No. 1. 



Le quatrihme muscle qui concourt a Velevation du demi bee superieur, Herissant, 1748, p. 345. 



Le second muscle externe de Vos quarre, Cuvier, vol. iii. p. 73. 



Attachments. — The levator quadrati arises from the posterior part of the roof of the 

 orbital cavity, below and under cover of the post-orbital process. Its fibres pass vertically 

 downwards, and are inserted into the ujaper border of the orbital process of the quadrate 

 bone. 



Action. — This muscle elevates the quadrate bone, and with it the upper jaw. 



Relations. — The levator quadrati lies in contact with the inner surface of the orbito- 

 maxillary muscle. 



Nerve supply (?) 



7. Pterygo-maxillans. 



Attachments. — This is a quadrilateral plate of muscular fibres which arises from the 

 upper surface of the pterygoid, and to a slight extent from the outer margin of the palate 

 bone. The fibres pass horizontally outwards and backwards, and are inserted into a 

 well-marked depression on the inner surface of the ramus of the lower jaw, immediately 

 below the articular surface of that bone. 



Action. — This muscle elevates the lower jaw and directs its anterior extremity 

 towards the opposite side of the body. 



Relations. — It lies on the floor of the orbital cavity, and rests upon the upper surface 

 of the pterygoid muscle. The depressor of the lower eyelid is in contact with its upper 

 surface. 



Nerve supply (?) 





/ 



( 







