146 THE SENSORIAL FUNCTION. 



and overlap eacli otlier, and thus, by rendering- the birth more easy, they 

 save the mother much pain, and contribute to the safety of the foal 



The first of these bones, or the first pair of them, occupying the broad 

 expanse of the forehead, are called the frontal hones, a a. They are 

 united too-ether by a most curious and intricate dove-taihng, to defend 

 the brain which hes beneath the upper part of them. Lower do^m, and 

 where the cavity of the nose is to be defended, their union is sufiicient, 

 but far less complicated. Thus, at first starting, there is an evident proof 

 of desicm, an illustration of that adaptation to circumstances which will 

 ao-ain and again present itself in the most interesting points of view. 

 Peculiar strength of union is given where a most important organ is to be 

 defended ^the suture is there intricate and laboured. Where less im- 

 portant parts are covered, it is of a far simpler character. The inner 

 plate of the frontal bone covers a considerable portion of the anterior part 

 of the brain, and it is studded with depressions corresponduig with 

 irregularities on the surface of the brain. 



Few things more clearly indicate the breed or blood of the horse than 

 the form of^the frontal bones. Who has not remarked the broad angular 

 forehead of the blood horse, giving him a beautiful expression of intel- 

 ligence and fire, and the face gi^adually tapering from the forehead to the 

 muzzle, contrasted with the large face of the cart or dray horse, and tlie 

 forehead scarcely wider than the face ? 



At/, between the frontal bones, is the pit or cavity above the eye, and 

 by the 'depth of which we form some idea of the age of the horse. There 

 is placed at the back of the eye a considerable quantity of fatty substance, 

 on which it may revolve easily and without friction. In aged horses, and 

 in diseases attended with general loss of condition, much of this dis- 

 appears ; the eye becomes sunken, and the pit above it deepens. It is said 

 that some of the lower class of horse-dealers puncture the skin, and, with 

 a tobacco pipe or small tube blow into the orifice, until the depression is 

 almost filled up. This, with the aid of a bishopped tooth, may give a false 

 appearance of youth, that will remain during some hours, and may deceive 

 the unwary, but the trickery may easily be detected by pressing on the part. 

 These bones, however, are not solid, but a considerable portion of them 

 is composed of two plates receding from each other, and leaving nunierous 

 and large vacuities or cells. These vacuities are called the frontal 



The sinus on the diSerent 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 shiuses afford a somewhat increased protection to the brain 

 beneath ; and by the continuous and slightly projecting line which they 

 form, afford lightness, while they give beauty to the forehead ; but their 

 principal use probably is, hke the windings of the French horn, to increase 

 the clearness and loudness of the neighing. It ^vill be remarked that they 

 are very irregular in depth, which at one place is an inch br more. 



Immediately above the frontal, and extending from the frontal to the 

 poll, are the parietal bones, c c. They are two, united together by a suture 

 when the animal is young, but that suture soon becoming obhterated. 

 They have the occipital, g, (p. 145) above, the frontals, a a, below, and the 

 temporals, d d, on either side. They are of a closer and harder texture 

 than the frontals, because they are more exposed to injury, and more con- 

 cerned in defending the brain. 



A very small portion only of the parietals is naked, and that is com- 

 posed of bone even harder than the other part, and with an additional 

 layer of bone rising in the form of a crest or ridge externally. Every 



