RUMINANT QUADR17PEDS. 501 



highest perfection of structure belonging to this 

 type. We may observe that the parts com- 

 posing the hind legs are longer, and inclined to 

 one another at angles more acute in these ani- 

 mals than in other tribes of mammalia, so that 

 they are always ready for instantly commencing 

 their flight, and springing forwards on the slight- 

 est notice of danger. (See Fig. 218, page 507). 

 As it was necessary, from the situation of their 

 food, that their heads should reach the ground 

 in grazing, we find that the neck has been much 

 elongated, that the muscles which raise the head 

 have been enlarged and strengthened, and that 

 the spinous processes of the back and neck have 

 been much expanded in order to allow of suffici- 

 ent surface for the attachments of these muscles. 

 The effort requisite to raise, and even support the 

 head is very considerable ; as will appear when 

 we reflect that its weight acts by means of an 

 extremely long lever ; for such is the mechanical 

 office of the elongated neck. But in order to 

 economize the muscular power, an elastic liga- 

 ment is employed to sustain the weight of the 

 head. This, which is termed the ligamentum 

 nucha, and is represented at N, in Fig, 217, is 

 formed of a great number of bands which connect 

 the hinder part of the cranium, at the ridge of 

 the occipital bone, and all the spinous processes 

 of the neck, with those of the back, the separate 

 slips from each being successively joined toge- 



