ODONTOGRAPHY. 73 



character, we can describe the roots from some of these. I ' will, therefore, 

 only remark further, that it corresponds with' the tooth on the other side of 

 the same jaw; and, like that, its cusps are very little worn. With the 

 corresponding tooth in the lower jaw of the same head, it agrees in almost 

 every particular. » 



The fangs, in the most perfect of the specimens of this tooth in my 

 possession, are five in number. The anterior root inclines backwards ; the 

 posterior, which is the longest, bends forwards ; the three intervening take 

 a direction between that of the two others. The anterior root is separated 

 from the rest, and supports the anterior ridge or- lobe. The four posterior 

 unite together, and support the corresponding ridges. Each of the roots 

 has the form of a cone. These fangs are accompanied with a body, of the 

 cellular bone of the upper jaw, which embraced them. 



The finest ultimate lower molar I have met with, was brought from ultimate 



Molar 



the banks of the Willamet river, in Oregon, by Captain Wilkes, of the from ore- 



gon. 



Exploring Expedition, and is now deposited in the collection at Washington. 

 Through the kindness of the Honorable R. C. Winthrop, Speaker of the 

 House of Representatives, I obtained a cast of this tooth, colored like 

 the original. It has a peculiar interest in having been discovered beyond 

 the Rocky Mountains, at the distance of thousands of miles from the great 

 deposits on this side of the Mississippi, yet resembling the latter in every 

 essential character, at least in my estimation ; although, to those paleon- 

 tologists who are disposed to increase the number of species in this family, 

 it might perhaps afford distinctive characters sufficient to constitute a new 

 sjjecies. The peculiarities are, 1st, its greater size than that of the others ; 

 2d, in addition to five regular ridges, it has a talon ; 3«5, it has a very light 



color ; 4dh, the anterior fang is united with the mass of posterior fangs. 

 10 



