CHAPTER II. 



ANATOMY OF THE BEAVER. 



Introduction — Description — Skeleton — Skull — Teeth — Muscles — Internal 

 Organs : Mouth, Stomach, Intestines, Caecum, Heart, Lungs, Liver, 

 Spleen — Respiration of Aquatic Animals — Brain. 



Appendix A. 1. Measui-ements of Skull. 2. Differences between Euro- 

 pean and American Beavers considered. 3. Castoreum Organs, and Gen- 

 erative Organs. 



In the study of animals for the purpose of determ- 

 ining their zoological relations, it has been found 

 necessary not only to consider their external charac- 

 teristics, but also to investigate their internal struc- 

 ture. The distinction of species is often impossible 

 without the aid of anatomical research. In the case 

 of the beaver, the closely-allied European and Amer- 

 ican animals could not be distinguished by anything 

 in their external conformation. Anatomists resort, 

 therefore, to a minute investigation of the cranial and 

 other structures to discover essential points of diflfer- 

 ence. 



For this reason, some account of the anatomy of 

 the beaver seems appropriate to the present volume, 

 which, although popular in its character, is sufficiently 

 comprehensive in its design to admit of the introduc- 

 tion of the scientific element. A somewhat general 

 resume of beaver anatomy has been attempted in order 

 to give greater completeness to the work. It would 

 be impossible, in the limits of a chapter, to give all 

 the details belonging to this subject, which would re- 

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