HIPPOPOTAMUS. 137 



comparatively greater in the Sewalik fossil, and the extreme 

 width of jaw over the penultimate false molar less. It will 

 be seen that these differences of form correspond with those 

 of the skuU, the advanced position of the orbit and the con- 

 traction of the sinus, in which the infra-orbitary holes are 

 situated, leading to a modification in the whole form of the 

 grinding surface. 



Having made the comparison with the Cape and existing 

 Hippopotamus, we will cursorily note the differences that strike 

 us when comparing it with the fossil described by Cuvier as 

 belonging to the cabinet of the Grand Duke of Tuscany, and 

 figured in the first volume of the ' Ossemens Tossiles.' The 

 distinctive differences will be, perhaps, best observed by a 

 reference to the table of measurements ; we see, however, that 

 our fossil in the gradual slope of the malar process towards 

 the cheek corresponds, but differs completely in the hollow 

 formed, at this point, between the jugal bone and canine 

 alveolus, which in our fossil is more abrupt and marked. The 

 length of the parietal region of the European fossil is even 

 less than that of the existing animal, and its proportions 

 relatively with the bones of the face less. In the Sewalik 

 fossil the advanced position of the orbit completely modifies 

 the whole form, and, by equalizing the proportions of the 

 anterior and posterior divisions, gives a new style of appear- 

 ance to the cranium. In the fall of the occipital crest towards 

 the region between the orbits and a consequent height of 

 occipital surface, the Sewalik and Florence fossils agree. 

 In the proportion of the frontal surface to the area of the 

 rest of the skull, the resemblance also holds good ; but we 

 have the same difference in the relative position of the 

 canines to the molars ; the Florence and African species 

 corresponding in this respect. The grand distinction of the 

 incisives and canines, both in form and number, is peculiar to 

 the Hippopotamus Sivalensis. In the lower jaw, the space 

 between the two branches and the angle which is internally 

 formed by them do not resemble those of the Florence 

 fossil, but, as we before remarked, are more assimilated to 

 those of the existing animal, in being round at the angle, and 

 the whole interval space being more open : the descending 

 process of the ramus differs, as explained before ; and the 

 form of the anterior angle of the jaw below the canines is 

 somewhat similar and not so gradually rounded off as in the 

 living animal. The difference in size and number of the in- 

 cisors leads to a difference which, as before noted in the 

 comparison with the living animal, needs not be made the 

 subject of further remark here. 



With the Hippopotamus Sivalensis and that figured in the 



