362 NAVIN ON THE HORSE. 



BONES OF THE EAR. 



These are four small bones connected with the internal part 

 of the ear, and curiously arranged, and so delicately poised 

 as to be moved by the slightest jar or vibration of the air in 

 the external part of the car. There are, of course, eight in 

 both ears. They are named the ??i<x/^e«i5, or mallet; the incuSj 

 or anvil ; the stcq^cs, or stirrup, and the os orliculare, or round 

 bone. The handle of the mallet is attached to the drum of 

 the ear, and its face rests on the anvil. The incus resembles 

 a blacksmith's anvil in shape; hence its name. It has a de- 

 pression in which the head of the hammer rests. The staj)eSf 

 or stirrup, is the shape of a common iron stirrup, and is con- 

 nected with the incus by the os orUculare, or round bone. The 

 orhicuUre is a round bone, not larger than a grain of mustard- 

 seed. It enables the incus and staj^es to move more freely. 



THE BONE OF THE TONGUE. 



This bone is situated at the root of the tongue, the body of 

 the bone lying crosswise. From the middle part a sort of pin- 

 shaped spike of bone is inserted into the root of the tongue. 

 Each end of the body has two horns. The shorter ascend 

 obliquely and terminate in smooth extremities. The longer 

 horns extend backward. Its use is to give attachment to the 

 muscles principally concerned in swallowing, and to support 

 the tongue and other soft parts of the mouth. 



THE MUSCLES. 



The muscles constitute the fleshy part of the animal. They 

 have a red appearance, and form the great bulk of the animal 

 body. They differ very greatly in size and length, some being 

 very heavy, weighing many pounds, and several feet in length, 

 while others are so delicate and small as to be very difficult to 

 find, even by the anatomist. All muscles, however, have cer- 

 tain general characters, which will now be explained. 



