64 Dr Graves on the Vertehroc of the Whale. 



on the Anatomy of Whales, it must, nevertheless, have been 

 known to several. If we find that the terminal epiphysis has 

 become completely united to the body of the vertebra, we may 

 be assured that the bone, whether large or small, belonged to 

 an animal arrived at maturity ; but if not, we may conclude 

 that it had not yet attained to its greatest size. To facilitate 

 this inquiry, I may remark, that a very slight examination of a 

 vertebra is sufficient to determine, whether the epiphysis has or 

 has not been detached; as in the former case the surface is 

 marked hy deep ridges and furrows diverging Jrom the centre 

 towards the circumference ; whereas in the latter, if the animal 

 was of moderate size, the marking consists of concentric lines, 

 answering to the attachments of the intervertebral substance ; 

 and if the individual was very large, these concentric lines are 

 exaggerated into concentric furrows ; and whether the attach- 

 ments of the intervertebral substance be marked by concentric 

 lines or by concentric furrows, a considerable portion of the 

 central part of the hone, where it had been in contact with the 

 intei'nal substance of the intervertebral ligaments, is quite des- 

 titute of this marJcing, and presents a striking contrast to the 

 rest of the surface. 



I am not aware that the true cause of this remarkable differ- 

 ence between the markings on the extremities of the vertebrae 

 of the cetacea has been before explained. 



It may not be uninteresting to add, that the cranium of the 

 Delphinus diodon in my possession, and both those in the Mu- 

 seum of the College of Surgeons, present, in a very remarkable 

 manner, the want of symmetry between the right and the left 

 sides of the cranium, which was first observed by Meckel in 

 the skulls of the cetacea. 



Note Since the preceding notice concerning the hock-joint of the horse, 



was submitted to the Academy, I have had an opportunity of examining two 

 horses affected with string-halt, and am inclined to attribute the disease to a 

 spasmodic affection of the flexors of the limb generally, rather than to any 

 derangement in the structure of the hock-joint. It may be right to mention, 

 that the following authors on Comparative Anatomy, and the Anatomy of 

 the Horse, have been searched, but they contain no notice of the peculiarity 

 in the structure of the hock-joint, above described : — Macartney, Cuvier, 

 Carus, Blumenbach, Meckel, Clater, Blaine, Stubbs, Percivall, Boardman, 

 White, Lawrence, Osmer, Home, Bourgelat. 



