HIPPOPOTAMUS. 139 



again on the opposite side just between and under the fourth 

 and fifth molar, in a markedly large hole from which, to the 

 space between the tusk and the most advanced molar, there 

 is a deep channel or indentation running upwards in a curved 

 line parallel to the lower face of the jaw. The anterior and 

 posterior portions of this beautiful fragment are unfortunately- 

 wanting, but a small part of the symphysis, at which point 

 the fossil terminates, is distinctly marked, as well as the 

 transverse section of the canine or tusk which, as in the large 

 animal, is pear-shaped. A considerable portion of the anterior 

 extremity is wanting, and with the tusk the fracture shows 

 only one alveolus or hollow for an incisive tooth ; the exist- 

 ence of two, however, can hardly be doubted, but the 

 narrowness of the front may make a greater number than 

 four between the two canines problematical.' The ramus of 

 this specimen is strongly marked on its anterior part by an 

 elevated ridge pointing angularly forwards, and pushing 

 forward a nearly flat surface to the centre of the rear tooth ; 

 the descending process is unfortunately too much broken to 

 allow of our speaking decidedly, but the angle of departure 

 from the straight line of the jaw is abrupt (PI. XIII. fig. 3). 

 The other remains of this smaller species to which we have al- 

 luded consist of a skull, the front and rear of which is broken 

 off, and one line of molars with the palate only perfect. The 

 superimposed cranium would appear to be contorted by pres- 

 sure, as is by no means uncommon, but this circumstance 

 would lead us to refrain from an attempt at characterizing 

 its i^eculiarities. The molars consist of the three rear per- 

 manent ones, and the last false molar, this latter one exhibit- 

 ing the crescentic form of wear on its coronal surface, described 

 as peculiar to the first fragment. The other molars are much 

 worn, and, therefore, with the exception of the encircling 

 ridge of enamel, we have not those flexures which Avould 

 have brought us to a correct conclusion. These molars are 

 remarkably broad in proportion to their antero-posterior 

 dimensions, and have an oblique grinding surface, as before 

 described in the other fragment. We may remark, that, 

 should these two remains belong to a small Hippopotamus of 

 the same species, the great difference in the breadth of the 

 grinding surface in the upper and lower jaws, as marked as 

 it i« in the Rhinoceros, would establish a species with (in this 

 respect) rather unusual peculiarities. To this smaller species 

 we propose the name of dissimilis, from the differences of 

 form from the rest of the genus. 



From the above additions to the species of the Hippo- 



' Subsequent specimens showed that there were six incisors. See Plate xiii. 

 fig. 4.-[Ed.] 



