746 Specific characters of Bibos, [Sep*. 



in its present crude state, this prolixity cannot be avoided. You 

 already possess a good delineation of the skull* : I subjoin herewith 

 one of the bony trunk. From the combined characters of the two I 

 deduce my subgeneric designation ; and to prove the fixedness of 

 those characters, I may add that they are equally conspicuous in both 

 sexes; the most remarkable perhaps of them — viz. the signal deve- 

 lopment of the spinous processes of the dorsal vertebrae, being also 

 fully revealed in the foetus in uterof ! 



The trunk I have sketched for you} is that of a female ; and you 

 have but to compare it with the trunk of a cow (any breed) to per- 

 ceive in how signal a degree the superior length of the spinous pro- 

 cesses adverted to, distinguishes Bibos. Owing to this osteological 

 peculiarity, the back of the living animal, when the head is down (as 

 in the act of grazing) describes almost half a circle from nape to tail. 

 But, owing to the slight development of the analogous processes of 

 the cervical vertebrae, and to the extraordinary height of the frontal 

 crest of the head, the state of quiescence in the living animal (the 

 stand at ease) exhibits a deep fall between the head and shoulders, 

 Very unlike the continuous downward sweep from nose to croup 

 which is attributed to the Bisons, and is ascribed in them to the deve- 

 lopment of the spinous processes of both cervical and dorsal vertebrae, 

 half and half in both. If this be so, the position of the ridge will 1 

 constitute the distinction, quoad hoc, between Bibos and Bisonus, as 

 the possession of it by both will constitute ^strong affinity between 

 the two groups, and one which it is of peculiar importance to mark, 

 with reference to those principles by which structure seems to be 

 governed throughout the ruminating animals. 



On the other hand, the relationship of Bibos to Bos proper is suffi- 

 ciently apparent in their common possession of thirteen pairs of ribs, 

 a broad flat forehead, (exclusive of the peculiar frontal crest) and a 

 smooth glossy fine coat, though the value of the last character may be 

 open to reasonable objection. 



The size and weight of the skull in Bibos, as compared with Bos 

 proper, are vastly greater than general proportion would require, if 

 they were organized on the same principles : and to this superior 

 weight of the head in the former must be referred, as to its cause 

 that signal development of the spinous processes of the dorsal vertebra 

 spoken of. 



* See Plate XVI. of the present volume. 



f I recently procured a specimen of the foetus from the mother's womb. I 

 was about two months old. 

 X See Plate XXXIX. 



