112 THE SENSORIAL FUNCTION. 



4) 



d The tentorium or bony separation between the cerebrum and cerebellum. 



e The occipital bone. 



f The ligament of the neck, or pack-wane, by which the head is chiefly supported. 



g The atlas, sustaining or carrying; the first bone of the neck. 



h The dentata, tooth-like, or second bone of the neck. 



t The cuneiform, or wedge-shaped process, or base of the occipital bone. Between it and 

 the other portion of the occipital bone e, lies the great foramen or aperture through 

 which the prolongation of the brain the spinal marrow issues from the skull. 



k The sphenoid, wedge-like, bone, with its cavities. 



I The ethmoid, sieve-like, bone, with its cells. 



TO The cerebrum, or brain, with the appearance of its cortical and medullary substance. 



n The cerebellum, or little brain, with its beautiful arborescent appearance. 



A portion of the central medullary, marrow-like, substance of the brain, and the prolonga- 



tion of it under the name of the crus cerebri, leg of the brain, and from which many 



of the nerves take their origin. 

 p The medulla oblongata the prolongation of the brain after the medullary substance of the 



cerebrum and cerebellum have united, and forming the commencement of the spinal 



marrow. The columnar appearance of this portion of the brain is represented, and the 



origins of the respiratory nerves. 

 q The spinal marrow extending through a canal in the centre of the bones of the neck, back, 



and loins, to the extremities of the tail, and from which the nerves of feeling and of 



motion, that supply every part of the frame except the head, arise. 

 r The septum narium, or cartilaginous division between the nostrils. 

 s The same cut off at the lower part, to show the spongy turbinated, turban-shaped, bones 



filling the cavity of the nostril. 

 t The palate. 



u The molar teeth, or grinders. 

 v The inferior maxillary bone, containing the incisor teeth or nippers. The canine tooth or 



tush, is concealed by the tongue. 



w The posterior maxillary, or lower jaw with its incisors. 

 x The lips. 

 y The tongue. 

 z A portion of the os hyoides, or bone of the tongue, like a Greek tt, u. 



1 The thyroid, helmet-shaped, cartilage, inclosing and shielding the neighbouring parts. 



2 The epiglottis, or covering of the glottis, or aperture of the wind-pipe. 



3 The arytenoid, funnel-shaped, cartilages, having between them the aperture leading into 



the trachea or wind-pipe. 



4 One of the chord* vocales, cords or ligaments concerned in the formation of the voice. 



5 The sacculus laryngis, sac or ventricle of the larynx, or throat, to modulate the voice. 



6 The trachea or wind-pipe, with its different rings. 



7 The soft palate at the back of the mouth, so constructed as almost to prevent the possibility 



of vomiting. 



8 The opening from the back part of the mouth into the nostril. 



9 The cartilage covering the entrance into the eustachian tube, or communication between 



the mouth and internal part of the ear. 



10 The oesophagus, or gullet. 



1 1 The cricoid, ring-like, cartilage, below and behind the thyroid. 



12 Muscle of the neck, covered by the membrane of the back part of the mouth. 



The sinus on the different sides of the forehead do not communicate with 

 each other, but with other sinuses in the ethmoid, and sphenoid, and upper 

 jaw-bones, and also with the cavities of the nose on their respective sides. 

 These sinuses afford a somewhat increased protection to the brain beneath ; 

 and by the continuous and slightly projecting line which they form, they give 

 beauty to the forehead ; but their principal use probably is, like the windings 

 of the French horn, to increase the clearness and loudness of the neighing. It 

 will be remarked that they are very irregular in depth, which at one place is 

 an inch or more. 



In the sheep, and occasionally in the ox rarely in the horse the larvae of 

 maggots produced by certain species of flies, crawl up the nose, lodge themselves 

 ill these sinuses, and produce intolerable pain. 



Veterinary surgeons have availed themselves of these sinuses, to detect the 

 existence of glanders, that disease so infectious and so fatal. They may sus- 



