12 



palpebrarum, the use of which seems to be, to elevate the lower lid ; pos- 

 terior and superficial to it is a venous plexus, formed of the veins of the 

 head and face uniting to form a single trunk, which passes to the jugular 

 vein. A strong palpebral ligament extends from the brim of the orbit all 

 round into the lid, to strengthen it. Levator palpebrae superioris arises 

 within the orbit, from the bony surface forming the posterior portion 

 of the roof of the cavity ; the fibres run outwards, and are inserted into 

 the tarsal border of the lid. A small anterior bundle of muscular fibres 

 passes from the inner or anterior angle of the orbit to the inner can- 

 thus of the lids; this seems to be also an elevator of the upper lid. 



The orbit contains the recti, obliqui, and the two muscles of the 

 membrana nictitans : the former arise around the border of the optic 

 foramen, united by a ligament of Zinn, stronger above than below. The 

 muscles of the membrana nictitans are, as usual, quadrate and triangular ; 

 nothing of peculiarity is noticeable in their arrangement, except that 

 from their greater size they are better seen than in most birds. They 

 are supplied by the third nerve, and the tendon of the triangular muscle 

 grooves the sclerotic posterior to the bony plates. External to the trian- 

 gular muscle, andbetween the inferior and internal rectus, is placed a large 

 oval Harderian gland, embedded in cellular tissue, and compressed, pro- 

 bably by the triangular muscle when acting, so that its secretion is 

 forced out, and is conveyed by a duct to the inferior and inner border 

 of the attachment of the membrana nictitans. A peculiar gland is found 

 embedded in the depression on the side of the frontal bone, separated 

 from the nose by a strong membrane, through which its duct seems to 

 penetrate. All the parts in the orbit are surrounded by the layers of a 

 loose ocular fascia. 



There are two elevators of the lower jaw, closely connected. Tem- 

 poral arises from the deep fossa behind the orbit, and is inserted into 

 the coronoid process of the lower jaw ; the other lies more horizontally, 

 and arises posterior to the last from the hinder portion of the temporal 

 fossa, almost as far back as the occipital bone ; from this origin it passes 

 downwards and forwards, to be inserted into the ramus of the lower jaw 

 in front of the coronoid process, here overlapping the last. A large 

 glandular mass fills up part of the interspace between these muscles, in 

 contact with the forementioned venous plexus. 



In dissecting the neck, a large platysma is first seen, which below is 

 attached to the furculum, and above to the integument, as high as the 

 head ; its outer fibres are oblique, and the inner vertical ; it is thicker 

 and stronger in front than behind ; beneath it, at the upper part of the 

 throat, is the larynx and its muscular apparatus, and in our dissection 

 we meet with the following : — 



Mylo-hyoid — flat and triangular — arising from a ridge on the anterior 

 four- fifths of the lower maxilla, in contact with the mucous membrane 

 of the mouth ; the fibres pass inwards, and are inserted along with the 

 opposite muscle into a median raphe ; a few of the most posterior are 

 attached to the os hyoides. 



Maxillo-keratic is a long flat slip, passing from the lower jaw a little 



