44 THE AMERICAN BEAVER. 



American beaver skulls to ninety-eight. Beside these, 

 seven American skulls and one European were loaned 

 from the Smithsonian Collection, and two American 

 from the New York State Collection, which increased 

 the w^hole number of American skulls examined to 

 one hundred and seven. A comparison shows that 

 the several variations between the skulls of the 

 European and American beavers, claimed to exist by 

 Brandt, are not constant; that the supposed differ- 

 ences shade off into each other and disappear, and 

 that the tendency to diverge, which plainly exists, is 

 no greater or stronger than would be unavoidably due 

 to the long-continued separation of these stocks, and 

 to climatic influences inseparable from their widely- 

 extended habitat. If brought together, they would, 

 without doubt, produce, inter se, a fertile offspring. 

 The anatomical differences between them are probably 

 less than between individuals of the most strongly 

 contrasted families of mankind. It will not be neces- 

 sary to present the comparative measurements in this 

 connection, as they are fully given in Appendix "A," 

 to which the reader is referred. The tendency to 

 variation, however, is sufficiently marked to charac- 

 terize the American and European beavers as varie- 

 ties of the same species, which is the most that can, 

 at present, be claimed. This would fix the nomencla- 

 ture for the first as Castor Fiber, var. Americanus, 

 and of the second, as Castor Fiber, var. Europseus. 



The beaver, in the duration of his distinctive type, 

 is one of the oldest of living mammals. He is also 

 shown to have been the cotemporary of many species 

 now extinct. His coarse subsistence, aquatic habits, 

 rugged strength, and prolific nature, eminently fitted 



