188 THE EQUID^ IN GENERAL. 



that we must chiefly refer these powers. In the 

 wild ass, where we also find very gTeat speed, a 

 vertical shoulder and low withers prevent additional 

 weight being carried in a similar manner and with 

 equal convenience. 



Equidae are essentially grazing animals, all are 

 tempted by thistles, thorny shrubs, and brooms, 

 but none of them digest their food so completely as 

 not to leave the power of vegetation to many seeds, 

 especially of gramineous plants and tritica that 

 have passed through the stomach and are lodged in 

 their dung ; while their fondness for brambles, and 

 their active energy, tends to spread them over barren 

 plains, where they are thus made agents for intro- 

 ducing new plants, and gradually increasing the 

 vegetation, prepare whole regions to support both 

 vegetable and animal life in a multiplicity of forms 

 previously impossible. * They are gregarious : in 

 common with ruminants they see well in the dark, 

 have the pupil rather elongated, the eyes being- 

 placed far apart so as to enable them when the 

 head is down to view objects with facility before 

 and behind them, as well as sideways : the length 

 of head and neck is nearly equal to their height, 

 giving the power of cropping the herbage by means 

 of their flexible lips and well-set nipping teeth, to 

 accomplish which they are nevertheless obliged to 

 throw one of the fore-legs forward and the other 



* In this manner the Pampas, towards the Straits of Magel- 

 lan, are altering for the better, according to the observation of 

 llx. BartJett. 



