13 



in front of its condyle, to be inserted into the concavity of the great cornu 

 of the os hyoides, round which it winds. A small muscular slip runs from 

 the great cornu of the os hyoides on one side to the opposite, probably 

 acting as an approximator. Genio-hyoid — flat and straight — runs from 

 the lower surface of the centre of the lower jaw, passing backwards to 

 be inserted into the body and root of the great cornu of the os hyoides ; 

 beneath this pair is the upper quadrilateral projection of the os hyoides, 

 continued into the very short tongue. Hyoglossus, a very short muscle, 

 passes from the sides of the body of the os hyoides, as far forwards as to 

 the tip of the tongue. 



Numerous small muscular slips exist on the anterior aspect of the 

 larynx : one — hyo-laryngeus — passes from the back of the os hyoides to 

 the upper border of the thyroid cartilage, and several small transverse 

 slips unite the cornua of the thyroid cartilage. Thyro-hyoid — small, trans- 

 verse — passes from the oblique line on the front of the thyroid cartilage, to 

 be inserted into the great cornu of the os hyoides. Sterno- tracheal — three 

 feet and a half in length — arises from the posterior surface of the top of 

 the sternum by a round muscular slip, which is reflected inwards on the 

 side of the trachea, three inches above its bifurcation ; from this point 

 the muscle passes upwards, being adherent to the cartilaginous rings as 

 it ascends, the fibres expand, and finally are inserted into the lower 

 border of the thyroid cartilage, some passing as far as the os hyoides. 

 On the side of the thyroid cartilage a small muscular slip passes to the 

 back of the os hyoides. In the substance of the tongue a few longitudi- 

 nal muscular fibres or linguales can be traced on either side of the middle 

 line. The upper larynx exhibits two vocal cords, which are more than 

 half cartilaginous. There is no epiglottis ; the muscles seated here are 

 principally the proper arytenoids and posterior dilator muscles ; a pair of 

 thyro-arytenoids may also be seen. There is no lower larynx. The trachea 

 is made up of complete cartilaginous rings, forming a tube three feet 

 nine inches in length, behind which lies the oesophagus, with a plicated 

 lining membrane, which begins above in a dilatation or pharynx ; on 

 either side of the upper part of this sac lies a large glandular mass or 

 tonsil, opening by several ducts, which communicate with racemose 

 gland cavities. The jugular vein, which lies in front of the carotid artery, 

 passes posterior and external to the oesophagus ; the arteries lie close 

 together, but do not communicate. 



In removing the upper portion of the skull, in order to expose the 

 brain, the bones are found extremely spongy, and united at the sutures. 

 "When they are removed, the encephalon is brought into view, invested 

 with a dura mater, arachnoid, and pia mater. The former is strong, and 

 does not present more than the rudiment of a falx; and the latter is found 

 passing into the ventricles on either side, forming a choroid plexus. The 

 cerebrum exhibits no convolutions on its surface, and is made up of two 

 hemispheres and two tubercles or optic lobes. The cerebellum lies pos- 

 terior and inferior to the cerebrum; and the medulla oblongata is a central 

 prominence, exhibiting no secondary subdivisions, connecting the spinal 

 marrow below with the encephalon above. The cerebellum consists of 



