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On comparing the skulls of the fossil rhinoceros with those of the ex- 

 isting species, the following differences are observed: 1. The skulls of 

 the fossil rhinoceros are, in general, much larger than those of the living 

 species; but as the skulls of the living species, which have been obtained, 

 may riot have been of the largest individuals, this difference is n$t such as 

 should be insisted upon. 2. The occipital surface, which in the recent 

 skulls is nearly perpendicular with the axis of the head, and which, in 

 the unicorn, even inclines forward, in all the fossil skulls, inclines consi- 

 derably backwards; which necessarily occasions the distance from the 

 nose to the occipital ridge to exceed considerably that from the nose to 

 the occipital condyles. 3. The meatus auditorius has its axis vertical in 

 the living species ; but, in consequence of the obliquity of the temporal 

 bones occasioned by the obliquity of the inclination of the occiput, this 

 axis is oblique in the fossil species. 4. The fossil species has two horns, 

 but the skull has nothing of the form of the bicorn of Africa. There is a 

 considerable space between the bases of the two horns in the fossil spe- 

 cies, whilst in the rhinoceros of Africa and of Sumatra the bases touch. 

 This difference evidently proceeds from the elongation of the skull in the 

 fossil species. The basis of the second horn, too, agreeable to the remark 

 of M. Adrien Camper, has a more raised, and embossed, and a much 

 more rugous surface, in the fossil, than in the existing species. 5. Instead 

 of the anterior apophysis of the superior maxillary bone being short, and 

 the intermaxillary very small, as in the bicorn of Africa, the fossil bicorn 

 had these parts very strong, and longer than in all the other species, 

 which renders the length of the nasal notch more considerable. 6. There 

 is in the fossil species a prominence on the superior part of the incisive 

 bone, which is not to be seen in the hicorn of Africa, in that of Sumatra, 

 nor in a young unicorn, which appeared to approach to that of Sumatra. 

 It was found only in the large unicorn, the skeleton of which is in the 

 National Museum. 7. The most important character in the fossil rhi- 

 noceros is the form of the bones of the nose, and their junction with the 

 incisive bones : in these respects it differs not only from the other rhi- 



VOL, in. 3 B 



