MAMMALIA. 29 



the " cloven hoof" arrangement attained perfection, working 

 on pulley-joints. These modifications of the feet are 

 illustrated in Fig 17. 



Except that they have a relatively large, highly- 

 developed brain, and curiously modified front teeth which 

 grow throughout life, the Hippopotamidse are very little 

 different from some of the early Eocene Artiodaetyla. 

 They have indeed completely retained the aquatic and 

 marsh-dwelling habit. Although the hippopotamus is at 

 present confined to Africa, it also ranged over a large part of 

 Europe and Asia in the Pleistocene period. Remains of fine 

 animals which cannot be distinguished by their bones and 

 teeth from the existing African Hippopotamus amphibius, 

 are not uncommon in England even so far north as York- 

 shire. A large mandible and other remains from the valley 

 of the Cam at Barrington, near Cambridge, are exhibited in 

 Pier-case 11. In this and the adjacent Table-case 6, there 

 are also teeth and bones of the same species from the 

 Thames deposits, from Bedford, Essex, Oxfordshire, and 

 Suffolk, and from the Norfolk Forest Bed. A mandible and 

 other bones from the Upper Pliocene of Mont Perrier, Puy- 

 de-D6me, France, besides remains from the Arno valley in 

 Italy, are likewise shown in Pier case 11. H. pentlandi is 

 a smaller species, whose bones and teeth occur in such 

 enormous accumulations in the caverns of Sicily, that they 

 were dug out and exported from Palermo for many years to 

 be calcined for use in sugar-refining. Eemains of the same 

 small species are shown from the caverns of Malta; and 

 there is a still more pigmy animal, H. minutus, whose bones 

 and teeth have lately been found in great abundance by 

 Miss D. M. A. Bate in the caverns of Cyprus (see Table- 

 case 6). The remains had probably been washed into the 

 caverns by streams and floods. Another small species, 

 M. madagascariensis, of which a reconstructed skeleton is 

 exhibited in Pier-case 11, seems to have been quite common 

 in Madagascar at a late geological period. No hippopotamus 

 now lives in Madagascar, and the bones and teeth of this 

 small species exhibit so many variations, that it doubtless 

 had a severe struggle for existence. Although the hippo- 

 potamus is now extinct in India, several species lived there 

 in the Pliocene and Pleistocene periods, as shown by the 

 Cautley Collection in Pier-case 12 and Table-case 6 (Fig. 18). 

 The Miocene and earlier representatives of the family still 

 remain to be discovered, most likely in Africa. 



