392 



ACCOUNT OF A BELUGA 



in the loins, near to their extremity, receiving be- 

 tween them the sacral margin of the spinous pro- 

 cess, immediately before. In this structure, as in 

 that of a great number of fishes, where the gene- 

 ral appearance is somewhat similar, the spinal mar- 

 row may be examined, without disturbing the ver- 

 tebrae or their processes. In this animal, a consider- 

 able portion was taken out from the lumbar verte- 

 bra?, and was found to be covered with a semicylin- 

 drical mass on each side, formed of a tough, spongy, 

 elastic substance, with large bloodvessels running 

 through it, and anastomosing frequently and freely 

 at very small distances. From the elasticity of 

 this substance, the mouths of the bloodvessels re- 

 mained quite open on a transverse section; and from 

 that circumstance were very easily discovered and 

 injected, although they might have been easily tra- 

 ced without such assistance. These two semi- 

 cylinders occupied by far the greater part of the 

 spinal canal ; the medullary cord, where we exami- 

 ned it, not being larger than that of a man at the 

 middle of the neck. 



The intervertebral ligaments, though deeper, are 

 in structure similar to that of man and of various 

 quadrupeds, composed of a number of concentric 

 layers, and these layers of a fibrous structure, the 

 fibres of the contiguous layers decussating like the 

 layers of the intercostal muscles. In the centre of 

 these ligaments was a soft substance resembling a 

 mixture of jelly and cartilage. In the back and 



