ON THE BONKS OF THE HIPPOPOTAMUS. 403 



fallen under my observation, are, to those of the living subject, in the 

 proportion of 3 to 2, which would give the animal's length at sixteen 

 feet and a half. It is that of the right side. 



The Calcaneum (plate 37, figs. 13 and 14), has its great astragalian 

 process larger towards the top, adapting it to the reception of that of 

 the astragalus. I likewise find that it is more elongated in proportion 

 to its height, for its height is, to the distance of its tuberosity from 

 the astragalian process, as 1 to 2§, while in the living subject it is as 

 1 to 2. The fossa for the tendon of Achilles is shorter, the tuberosity 

 of its inferior surface is much less prominent ; its third astragalian 

 process is not so high ; the cuboid process is larger ; in a word, the 

 practised eye discovers, at a glance, that it is a calcaneum of the same 

 genus, but of a different species. 



My two best calcanea belong to the left side : their total length is, 

 to that of the living subject, as 9 to 7: they must have proceeded 

 from a subject of about fourteen feet three inches. 



The Cuboid of the Tarsus (plate 37, figs. 7 and 8), has its astraga- 

 liau process broader behind in the fossil ; it is not there separated 

 from the fossil by so deep a slant ; it is not slanted at all at its internal 

 edge. The rhombus of its inferior surface is more oblique, and its 

 posterior inferior tuberosity much less prominent towards the base. 



I have had a very perfect one belonging to the right side ; it 

 was, to that of the living subject, as 7 to 5 : the animal must have been 

 about fifteen feet and a half ; a first left metatarsal bone of a subject 

 more than fourteen feet and a half does not offer any decided dis- 

 tinction ; but a second right bone of the same part (plate 37, fig. 15), 

 though equal to the corresponding one of the living animal, in length, is 

 broader by a fifth, and its upper head is cut more into right angles. 



I have a first phalange of one of the middle toes of the hind foot, 

 which only differs from the corresponding one of the living subject, 

 by its dimensions being greater by a fifth. 



7. Conclusion, 



It is now quite clear, that notwithstanding the general resemblance 

 of these bones with those of the living animal, they all afford suffi- 

 cient characteristics to lead us to acknowledge a difference of species, 

 and that the great fossil hippopotamus does not prove an exception to 

 that rule which affects the elephant, the rhinoceros, and the other 

 pachydermata of our changeable strata. 



With respect to the two other species of the fossil hippopotamus, 

 this rule applies to them in its fullest extent, and even with more force 

 and propriety than to the elephants, which shall be further illustrated 

 in the following article. 



Additions to this Article. 



Subsequently to the printing of this article, I have received the 

 eighteenth volume of the Memoirs of the Italian Society of Sciences, 

 in which I find, at page 415, an excellent dissertation from the pen of 

 Profesbor Nesti, on the fossils of the Valley of Arno. This learned 



