64 



THE NON-RUMINANT OR MANY-TOED ARTIODACTYLA. 



we can observe a liability to sudden accesses 

 of fury, the causes of which it is difficult to 

 guess, though they may be so violent as to 

 lead the animals affected thereby to dash 

 blindly against everything that stands in 

 their way. Yet among all the orders of the 

 Mammalia this is probably the one that is 

 most useful to man, who derives the greatest 

 advantage from it in respect of clothing, food, 

 and labour. If in civilized countries it is 

 impossible to dispense with the hollow-horned 

 animals, such as the ox, sheep, and goat, 

 which yield us their wool, milk, and flesh, 

 and are in part an important aid in field 



labour, the steppes and the deserts would be 

 impassable without camels, and the existence 

 of the Polynesian and Malayan races would 

 be endangered if they were deprived of pigs, 

 as that of the Polar races would be impossible 

 without the reindeer. 



We adopt two subordinate groups or sub- 

 orders: the Non-ruminant many-toed forms 

 (Polydactyla), which comprise the hippopo- 

 tamuses and the pigs, constituting one; and 

 the Ruminants (Bidactyla), to which belong 

 the musk-deer, the true deer, the hollow- 

 horned animals, the giraffe, and camels con- 

 stituting the other. 



GROUP OF THE 

 NON-RUMINANT OR MANY-TOED ARTIODACTYLA 



(POLYDACTYLA). 



THE HIPPOPOTAMUS 

 OR RIVER-HORSE FAMILY 



(OBESA). 



The River-horses (Hippopotamus) rival and 

 even, if possible, surpass the rhinoceroses in 

 ugliness. They form a specially African 

 type, which consists of only two species, the 

 smaller of which {//. /idertenszs), almost a 

 dwarf form, hitherto found only in the repub- 

 lic of Liberia, is but little known. This 

 dwarf species, which has many affinities to 

 a fossil form found in Europe (//. minor), 

 attains only the size of a tapir, while the 

 well-known species kept in our zoological 

 gardens, the Common Hippopotamus [H. 

 amphibius), which inhabits the whole of Cen- 

 tral Africa, and even extends to the Cape, 

 and which is figured in a full-page illustration 

 (PI. XXII.), attains a length of about 15 feet 

 and a weight of about 2^/^ tons. 



It is with good reason that the river-horses 

 have been taken as the type of a separate 

 family under the name of Obesa, the stout 

 animals. Everything about them is heavy 

 and large. The enormous belly almost drags 

 on the ground; the feet are short, massive, 

 somewhat twisted, and have four rounded 

 hoofs on the short toes, which are connected 

 together by an insignificant swimming mem- 

 brane; the neck is short and thick, the head 

 massive, long, and almost level on the surface, 

 the tail short and furnished with a few thick 

 bristles arranged in the form of a tuft. The 

 hide, at least three-fourths of an inch in 

 thickness, forms great folds on the shoulders 

 and thighs, and is quite naked except for a 

 few thinly scattered hairs in the folds. It is 

 of a dirty copper colour. There is no other 

 mammal which creates such an impression of 

 a formless mass of revolting nakedness as the 

 hippopotamus does. 



The enormous head has the form of an 



