MAMMALIA FACH Y DRRMATA. 4()I 



may he considered as merely an elonj^ation of the 

 nostrils, which have heen drawn out to suit a special 

 purpose, very different from the function to which 

 that part is usually sul)servient.* 



While tleetness and elasticity are the results of 

 the mechanical conformation of the horse, solidity 

 and strength are the objects chieHy aimed at in the 

 construction of the Pachydermata. The limbs have 

 a great weight to sustain, in consequence of the 

 huge size of the body ; and hence the several bones 

 which compose the pillars for its su})port, are ar- 

 ranged nearly in vertical lines. The joints of the 

 elbow and knee are placed low from the body; the 

 ulna in the fore legs, and the libnla in the hinder, 

 are fully developed, and are distinct from the 

 radius and the tibia. The number of the toes, 

 instead of being reduced to one, as in the horse, or 

 to two, as in ruminants, is here increased to five ; 

 though, in consequence of their being very short, 

 and of the skin which covers and surrounds them 

 being very thick, they hardly appear externally, 

 and are distinctly recognised only in the skeleton. 



It would carry me far beyond the limits of the 

 present work, were I to engage in a detailed exa- 

 mination of all the varieties of forms and structures 

 which occur in the mechanism of the different 

 tribes of mammalia, in reference to the purposes 

 they are intended to serve, and to the peculiar cir- 

 cumstances of the animal to which they belong. 1 



* A defective developement of the bones of the nasal cavity, while 

 the natural growth of the soft parts has continued, has often, in the 

 case of the human foetus, given rise to a monstrosity very much re- 

 sembling the trunk of the tapir or of the elephant. (See Geotfroy 

 St. Hilaire.) 



