ON THE BONES OF THE HHPOrOTAMUS. 407 



Here, then, we have the last molar of the great hippopotamus, as. 

 well as the two that precede if, most accurately represented in the small 

 one. There is no other animal whose germ can stand the same com- 

 parison, if we may except the pig : its three last grinders are almost 

 equal to this in size : moreover, the two first have four and the last 

 has five knobs; but these knobs are furrowed all round, and are ac- 

 companied by smaller knobs or accessory tubercles; so that the crown 

 of the tooth appears entirely covered with papillse, which is not the case 

 in my small fossil hippopotamus. 



From what I have stated in the preceding section, we may bear in 

 mind, that the three front grinders of the hippopotamus vary in form 

 and simplicity of shape from the three last ; we shall find the same 

 differences subsisting in the corresponding teeth of the smaller hippo- 

 potamus. 



One of them may be seen, plate 32, fig. 11. It is pyramidal, has 

 two thick roots, and, like the grinders, is worn obliquely on its back 

 surface, and at its point. Its base is 0,017 in length, and 0,013 in 

 hreadth. The height of its body, without the roots, is 0,01 5. A second 

 is represented, plate 32, fig. 10 : it is smaller, conical, compressed, and 

 worn on its summit alone. I have another of the same description. 



These anterior grinders, while bearing a strong resemblance to those 

 of the hippopotamus, have nothing in common with those of the pigs, 

 which are compressed, and which have a denticulated edge. 



But the best characterised teeth of the ordinary hippopotamus are 

 the incisors and the canines ; and it is with reference to these that 

 our small fossil species exhibits a perfect analogy with the great. 



Thus the lower incisors are cylindrical, ranged obliquely in front, 

 and worn only at their denticuli : I have found many similar to them 

 (the size excepted) in the stone blocks which I took to pieces : one of 

 these, almost perfectly entire, may be seen at plate 33, fig. 7. Its 

 diameter gives 0,01, and its length, as it is at present, 0,08. It cor- 

 responds with one of the lateral incisors of the common hippopotamus, 

 for the diameter of the latter gives 0,023, and the length 0,015. They 

 are more deeply striated on their surface than those of the smaller 

 species, their point is also more sharpened by detrition. 



Although the different species of pigs also have their lower incisors 

 very long and directed outwards, there is no possibility of confounding 

 them with those of my animal, because they are not cylindrical, but 

 prismatic or compressed at the sides. 



The lower canine teeth of the hippopotamus are inflected, so as to 

 form the arc of a circle. They are obliquely worn on the points of 

 their concave surface. 



My stone blocks have yielded me many of a similar description. I 

 have represented one of the best preserved in plate 33, fig. 11. It 

 bears a direct relation to the others in its proportions, for it has also 

 one half of the dimensions of the corresponding tooth of the great 

 species, viz. 0,02 in its great diameter, &c. Its surface offers some 

 differences ; the canines of the great hippopotamus are striated, or 

 rather deeply channelled along their entire length : the latter are 

 very delicately striated, and present, on their external surface, a hollow, 

 or species of very wide and very shallow canal, stretching along their 

 entire length. 



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