THE HEAD 



not only varies in form and size in diiferent animals, but also in the 

 same animal at different periods of life. In the young it presents a 

 striking prominence, but it becomes less marked as the animal grows older, 

 and as the frontal sinuses open out and their bony walls expand. 



The Nose. — The nose forms the greater portion of the lower division 

 of the front of the face. It is formed by the union of a number of bones, 

 and consists of two elongated cavities separated from each other by a thick 

 plate of cartilage (septum nasi) and communicating behind with the larynx 

 or upper part of the windpipe, and also with the pharynx, or throat. It 

 is broad and expanded, where it joins the 

 forehead, and gradually narrows as it proceeds 

 downward. It ends in two crescentic openings 

 — the nostrils, between which is a slight pro- 

 minence, the " nasal peak ". Laterally it is 

 limited by the eyes and cheeks. The form of 

 the nose, like that of the forehead, is subject 

 to variation with age. The bones on either 

 side of it, into which are implanted the fangs 

 of the molar teeth, subside as the latter 

 descend, giving to the face a sharp angular 

 appearance, and to the nose increased promi- 

 nence. This characteristic is especially marked 

 in old horses, and serves to distinguish them 

 from more youthful specimens. 



The Nostrils. — The nostrils are two 

 crescent-shaped openings situated at the lower 

 extremity of the head, right and left of a cen- 

 tral prominence, designated the " tip " of the 

 nostril or the " nasal peak ". They com- 

 municate with the right and left nasal passages respectively, along which 

 the air enters and leaves the lungs in the act of breathing. In conse- 

 quence of the long and pendulous condition of the soft palate (fig. 5), which 

 shuts off the mouth from the windpipe, respiration in the horse can only 

 take place through the nostrils. The.se orifices and the passages into 

 wdiich they lead are very capacious. Around the former are scattered 

 a few long coarse hairs, the roots of which are connected with nerves of 

 sensation. Like the hairs of the lips, they play the part of " feelers ". It 

 frequently happens, however, in our better-bred horses, that these tactile 

 organs are removed as a part of the equine toilet. If the nostrils be 

 opened (fig. 7) by drawing apart their edges, or, as they are technically 

 termed, alse, with the thumb and finger, there will be found, in addition 



Fig. 6. — The Head: Front View 



' Forehead. '' Poll. - Forelock. 

 ' Ear. * Supra-orbit. ' Eyebrow. 



^ Eye. ' Nose. * Nasal Peak. 



" Nostril. '" Upper Lip. 



