242 [Nov. 15 



grown*. The length of this bone is 11|^ inches. Now in the ske- 

 leton of the young giraffe belonging to the Zoological Society the 

 2nd and 3rd cervical vertebrae are exactly of the same length. The 

 authors infer, therefore, that in an animal nearly full-grown, such as 

 was that to which the detached bone at the College of Surgeons 

 belonged, the length of the 3rd cervical vertebra is 11^ inches ; and 

 consequently, that the length of the same bone in an animal which 

 has reached full maturity, is about 12 inchesf. 



That the fossil vertebra belonged to an adult which had long 

 attained its full size, is shown by the complete synostosis of the 

 upper and lower articulating surfaces, by the strong relief of the 

 ridges and the depth of the muscular depressions. But the length 

 of this bone is only a little more than eight inches. As the other 

 dimensions of the fossil and recent vertebrae that the authors placed 

 in apposition, are nearly in proportion to their respective lengths, it 

 follows that this fossil species of giraffe was one-third shorter in the 

 neck than an adult of the existing Nubian variety. 



But it was not only in size that the two giraffes differed ; they 

 differed also in their proportions. In the young giraffe at the Zoo- 

 logical Society the vertebra, which is 7^ inches long, has a vertical 

 diameter of 3" 8 inches; whereas in the fossil species the vertebra, 

 which is 8 inches long, instead of having a vertical diameter exceed- 

 ing 4 inches (as it ought, if its breadth were proportional to its 

 length), has a vertical diameter of only 3*6 inches. This goes to 

 prove that in this fossil giraffe the neck was one-tenth more slender 

 in proportion to its length than the neck is in the existing species. 



The inferior surface of the body of the vertebra is more curved 

 longitudinally in the fossil than it is in the recent bone ; the height 

 of the arc in the former case being to the height in the latter as 3 is 

 to 2. 



On the under surface of the fossil vertebra a very distinct longi- 

 tudinal ridge (b) runs down the middle, and this ridge is wanting 

 in the recent bone ; but this difference, probably, is chiefly owing 

 to difference of age. 



In the fossil vertebra the upper articulating head (<?) is very con- 

 vex ; for with a transverse diameter of 1*4 inch it has a vertical 

 height of 1 inch : laterally it is a good deal compressed. (See PI, III. 

 tig. 4.) 



The posterior articulating surface (d) forms a perfectly circular 

 cup, two inches in diameter ; and this diameter, in the immature 

 Nubian giraffe, is one- tenth greater, although the vertebra is one- 

 sixteenth shorter. This affords a further proof of the comparative 

 slenderness of neck in this fossil species. 



In regard to the apophyses, the inferior transverse processes (i, i) 

 are sent off downwards and outwards from the lower part of the 



* This appears from the detached state of the upper and lower articulating 

 heads of the bone. 



't' The height of the skeleton of the young giraffe in the museum of the 

 Zoological Society is lOi feet ; that of a full-grown Nubian giraffe is 16 feet. 



