Notice of the Tooth of a Mastodon. 53 



of the same volume. It is not the variety of C. tentaculata, which 

 Mich, called C. ros^rato in letters to Schk., as these are obviously 

 the same, for both are in my herbarium. 



O. rostrata, Mich., is a more stiff and less leafy plant than C. 

 xantho^hysa, Wahl., and has sessile spikes, while the other has 

 them on long exsert peduncles and recurved, and with stamens at 

 the apex as Mich, remarked ; and it has a short, hardly acute pis- 

 tillate scale, while the other has an ovate, acuminate, and long cus- 

 pidate scale but little shorter than the fruit. There can be no doubt 

 that the 0. rostrata, Mich, is identified, and is a distinct species. 



Art. VII. — Notice of the Tooth of a Mastodon ; by Jeffries 

 Wyman, M. D. 



The specimen from which the following description is drawn, 

 was deposited in the cabinet of the Boston Society of Natural 

 History, by the Rev. Howard Malcom, by whom it was obtained 

 at a place called Yea-nan-goung, situated on the banks of the Ira- 

 wady river, below Ava in Bur mah . It consists of a fragment of the 

 left lower jaw of a mastodon, containing one molar tooth entire, 

 excepting so much as has been worn away by the process of mas- 

 tication. As it differs materially from any of which a description 

 has been met with, it was thought worthy of a brief notice. 



The jaw is broken at the two ends of the tooth, the interven- 

 ing portion being entire. The whole specimen is sixteen inches 

 in length, and its circumference around the largest part two feet 

 two inches. The tooth measures twelve and a half inches in 

 length and four and a half in breadth. At the anterior extremity 

 is a portion of a denticule, of which the greater part has been 

 ground off; allowing that this had the same dimensions with 

 that which succeeded it, we shall have an additional length to 

 the tooth of an inch and a half, making the entire length one 

 foot two inches. The enamel is a quarter of an inch in thick- 

 ness, and its surface is rough from an incrustation of calcareous 

 matter. The denticules are eight in number, or nine counting 

 the one of which only a small portion remains, and project two 

 and a half inches above the alveoli. Each denticule uniformly 

 consists of four distinct mammillary points, symmetrically ar- 

 ranged. These are all separated from each other by a distinct 

 sulcus, the external ones being broad and stout at their base, and 



