1869.] 101 [Agassiz. 



As lias been said, there are no intermaxillaries to be recognized 

 as such, the superior maxillaries forming the apex of the jaw; and 

 the gristly mass lying upon their extremity, and containing the inci- 

 sor, being apparently the rudiments of those bones. 



Notes on Beaver Dams. By Alex. Agassiz. 



During a residence of nearly two years on Keweenaw Point, I had 

 occasion to examine a large number of beaver dams, most of them 

 still inhabited. I was particularly struck on visiting the first dam I 

 had ever seen, which is the largest dam of the district, measuring no 

 less than six hundred and fifty feet in length, and three and one half 

 feet in height, with the small number of lodges in the vicinity of the 

 pond. It seemed impossible that such an enormous structure could 

 have been built by the limited number of families which the lodges 

 would shelter. On examining other dams in more inaccessible 

 places, the same was found to be the case, the number of lodges is 

 small, the greatest number I have observed being five upon one pond. 

 It was evident from this that we possessed erroneous notions of the 

 gregarious nature of beavers, that they do not build their dwellings 

 crowded together like huts of working men round a mill, and do not 

 work together in great numbers, accomplishing the task of building 

 their dams in a short time; on the contrary it became evident that 

 their structures — their dams, their canals — are the work of a com- 

 paratively small number of animals, but to make up for the number, 

 the work of the succeeding inhabitants of any one pond must have been 

 carried on for centuries to accomplish the gigantic results we find in 

 some localities. This fallacy of our knowledge of the beavers was 

 first made public by Mr. L. H. Morgan, who, in his work on the 

 American beaver, which appeared during the last part of my stay at 

 Lake Superior, has given us a most capital history of the habits 

 of the beaver. I can only corroborate the truthfulness of his descrip- 

 tions by their perfect application to what I had seen of the beavers 

 in the district which I examined, and, state that I had arrived inde- 

 pendently at many of the conclusions which he has drawn from his 

 prolonged study, extending through twelve summers; it is refresh- 

 ing in these days of works filled with descriptions of species, to turn 

 to a monograph which reminds us of the times when the life history 

 of a single animal and the study of their habits was not considered 

 beneath the labors of a Huber or a Reaumur. 



