302 STRUCTURE OF THE SHEEP. 



The molar bones, comparatively larger in the sheep than 

 in the horse, and irregular in shape, are situated on the 

 sides of the face above the large maxillary, and partly 

 within and partly without the orbit of which they form the 

 lower part. 



The lachrymal bones, so called because the lachrymal 

 duct for the conveyance of the superfluous tears to the nos- 

 trils passes through them, is situated about half within and 

 half without the orbit, the latter portion being between the 

 molar and frontal bones — a diflferent arrangement from that 

 which obtains in the horse. The orbit or bony socket which 

 contains the eye is thus composed of a variety of bones. 



There is a long but very thin bone called the vomer, situ- 

 ated at the floor of the nostrils, and running throughout their 

 length, and having a groove into which is imbedded the car- 

 tilaginous substance which divides the nostrils into two equal 

 cavities. 



The posterior maxillary or lower jaw bone is formed of 

 two halves, united at the inferior part by cartilage in the 

 young subject and by bone in the adult. This united por- 

 tion forms the sockets for the eight incisor teeth, which 

 sockets, however, are by no means so deep or so strong in 

 proportion as in the horse, and thus it is common for sheep 

 to lose or break these teeth soon after they are fully devel- 

 oped. From the place of junction the lower jaw bones sep- 

 arate and gradually recede from each other, becoming wider 

 and deeper, and forming strong and secure sockets for the 

 molar teeth, after which the bones become thinner, turn up- 

 wards, and terminate in two extremities, one rounded, which, 

 with the temporal bone above, forms the maxillary joint, 

 which is secured from displacement by a hook-like projec- 

 tion which is the other termination of the lower jaw bone. 



The bones which we have mentioned as composing the 

 face are none of them solid in their structure, but most of 

 them hollow, and thus various cavities or sinuses are formed 

 which are called after the bones in which they appear. Ac- 

 cordingly we have the frontal, the maxillary, the sphenoidal, 

 the ethmoidal, and the palatine. The frontal are the largest 

 and most important, particularly in the horned sheep, in 

 which they are partly divided into cells and communicate 

 with other sinuses immediately surrounding the horn. These 

 singular cavities are not found in the young subject, but are 

 gradually formed as the size of the head increases. They 



