114 ARCTIC ZOOLOGY. 



connected with the existing wants of that animal. The op- 

 portunities aftorded me, however, of examining the structure 

 of the seal's heart were far from convincing that the foramen 

 ovale existed in the seal. The best investigator may be 

 mistaken from appearances ; but where the eye, as well as 

 the touch, is applied in evidence, and the alleged circum- 

 stance is not found, it may be pronounced hardihood to 

 bear out the story by assertion. I have anxiously tried to 

 ascertain the existence of such a passage between the 

 chambers of the vital reservoir in the animal now men- 

 tioned, but was in no instance able to trace any such per- 

 meation. 



Now instead of looking to this accidental passage in 

 the heart as essential to the continuation of life in animals 

 that seek their sustenai^ce in water, a more obvious resource 

 may be resorted to as explaining this phenomenon ; and 

 no division of animals presents this in better form than 

 the cetaceous, both from the magnitude of the scale, and 

 their peculiar habits. The extraordinary degree of warmth, 

 which is evident in the constitution of these animals, seems 

 at once to prove the existence of great abundance of arterial 

 fluid, which is the proper source of animal heat. In the 

 monodon, and B. mysticetus, this is strongly evidenced ; 

 the spinal canal containing scarcely anj^ of the substance 

 called medullary, and the jaw-bones, in their posterior 

 foramina, being of immense size, and like the spinal canal. 



