ON THE GREENLAND RIGHT-WHALE. 



123 





either side, by a very prominent angle, and to the two hindmost of these angles the first 

 chevron bone is attached. 



Thus at last the hindmost lumbar vertebra has attained to an ahiiost perfect resemblance with 

 the foremost caudal vertebra, as will be seen by the subjoined figure of these two vertebrae, 

 from our forty-four and a half feet long skeleton, in their natural connection (twelve times 

 diminished). 



It will be observed at once that the re- 

 semblance is produced, partly by the size of 

 the body being so much superior to that of 

 the arch, partly by the great diminution of 

 the spinous and transverse processes, and 

 finally and particularly by the form of the in- 

 ferior part of the body just described, by 

 which the aorta and its great lateral branch 

 is placed in a more sheltered position. 



It will also be seen that the first 

 caudal vertebra (when we put aside the less 

 essential differences in the measurements) can 

 only be distinguished from the last lumbar 

 vertebra by having the anterior, as well as 

 the posterior of these angles, provided with 

 articular facets for the chevron bones. By 

 the attachment of these bones the anterior 



corners are, on both sides, forced in a direction towards the posterior one, and the outer and 

 lower edge of the vertebral body assumes the form of a bridge above the lateral branches of 

 the aorta. 



Already in the most posterior part of the lumbar region, but still more in the most anterior 

 part of the caudal region, the intervertebral substance will be found to contribute very perceptibly 

 to the length of the spine. The first of the two last-mentioned vertebræ is eight and a quarter 

 inches, the other seven and three quarter inches long ; but in their natural connection they have 

 both together a length of eighteen and a quarter inches, and accordingly two and a quarter inches 

 must be occupied by the intervertebral ligamentous substance, which is here thicker than at any 

 other part of the vertebral column. Posteriorly in the caudal region this intervertebral substance 

 becomes gradually smaller, absolutely speaking at least, though not in proportion to the size of 

 the vertebræ. The second, third, and fourth caudal vertebrae, still united by the intervertebral 

 substance, measured twenty-five inches, while taken each by itself they measured seven and 

 three quarters, seven and a half, and seven inches, in the longitudinal direction of the body ; the 

 fifth, sixth, seventh, eighth, and ninth measured thirty-three inches in their natural connection, 

 their own length occupying seven, six and a half, six and a half, five and three quarters, and four 

 and three quarters inches, or, altogether, only thirty and a half inches. 



While the twenty-two caudal vertebrae gradually decrease in length, from seven and 

 three quarters to two inches, and their bodies diminish no less uniformly in point of height 

 and breadth, their arches and processes also gradually shrink into smaller dimensions, but 

 much more rapidly, so that the transverse processes have already disappeared from the sixth 



