ANATOMY OF THE BEAVER. 77 



1" 80'". Weight of cerebrum, 336 grs.; of cerebellum, 

 68 grs,; of medulla and peduncles, 69 grs.; total of 

 encephalon, 473 grs. The proportion of the marsu- 

 pial brain to the body in three animals, as stated by 

 Prof Owen, is 1 to 520, 1 to 600, and 1 to 614. In 

 the beaver it is 1 to 532. The average of the mam- 

 malia, according to Leuret, is 1 to 186; of birds, 1 to 

 212. In man it is 1 to 36. 



Note. — For description of the castoreum and generative organs 

 of the beaver, see Appendix A, Note 3. 



