Anatomical Structure of certain of the Cetacea. 409 



vertebra is remarkably thin and anchylosed to the second. There 

 are no openings in the transverse processes. The fourth, fifth, 

 sixth, and seventh cervical vertebras are distinct, having interver- 

 tebral cartilages interposed, and none of these is so weak as the 

 third. There are characters in which the narwal differs from 

 other Cete. No vestiges of openings for the vertebral arte- 

 ries in any of them. There are eleven dorsal vertebras, and 

 eleven ribs on each side. But Captain SCORESBY, whose autho- 

 rity in these matters is unquestionable, says, that there are twelve 

 dorsal vertebras, and, of course, twelve ribs, so that these bones, 

 in the skeleton now under consideration, may have been lost. 



In the Cetacea, apparently, the transverse processes of the 

 vertebras undergo a sudden elongation, about the termination of 

 the dorsal ones, that is the thirteenth vertebra. This we find to be 

 the case in the narwal under consideration. 



There are thirty-two remaining vertebras in the Barclayan 

 narwal, and twelve bones in the form of the letter V, which 

 bones may be considered as spinous processes on the ventral as- 

 pect of the vertebras. They are, however, placed upon the ver- 

 tebral substances, which renders their presence altogether ano- 

 malous. There are then in the narwal, 



Cervical vertebrae, 7 



Dorsal, carrying ribs, 11 



Lumbar and caudal, 32 



50 



The caudal may not be all present ; and as Mr SCORESBY says 

 that there are in the narwal he examined fifty-four vertebrae, 

 it is more than probable that four bones of the Barclayan spe- 

 cimen have been lost. 



