237 



M. augustidens and larger than in M. longirostris. " The outline of the jaw re- 

 sembles very much the figure in D'Orbigny's voyage, described by Laurillard 

 as M. andium. The Genoese paleontologists had named it Ehynchotherium, 

 from the enormous development of the beak, approaching t)inothermm." 



Perhaps this Mexican specimen of a lower jaw may pertain to the same 

 species as the specimens above described, though the beak of the New Mex- 

 ican specimen is unlike that of the figure above alluded to in the work of 

 D'Orbigny. 



The vertebral body and rib-fragment accompanying the jaw-fragments from 

 New Mexico present nothing remarkable. The former is of a lumbar verte- 

 bra, and would indicate an animal about as large as the living Asiatic elephant. 

 Its length is 34 lines ; its breadth is about 5 inches at the posterior border ; 

 and its height is 3£ inches. 



Mastodon mirificus. 



Some small fragments of jaws and teeth, apparently referable to this species, 

 in the museum of the Smithsonian Institution, were obtained by Mr. Clarence 

 King, from Sinker Creek, Idaho. 



Mastodon americanus. 



Among a collection of remains of the American mastodon, from Benton 

 County, Missouri, deposited in the museum of the Academy of Natural Sciences 

 of Philadelphia by the American Philosophical Society, there is a singular 

 tooth, which I suppose to be of abnormal character and to pertain to the 

 Mastodon americanus. The specimen is in the same state of preservation as 

 the associated remains, and is represented in Figs. 5 and G, Plate XXII. It 

 consists of the complete crown of a molar tooth without the tangs. Its shape 

 is so peculiar that I can form no clear idea as to the relative position it occu- 

 pied in the jaws, or as to its homologous character in comparison with normal 

 teeth. 



The crown in transverse outline is irregularly oblong oval, more bulging 

 on one side than the other, and somewhat prolonged at the extremities. From 

 a thick expanded base there project four conical lobes, of which the interme- 

 diate two are nearly equal and nearly twice the size of the others, also nearly 

 equal in size. The basal ridge on the more prominent side of the crown is 

 mammillated, and twice the depth that it is upon the other side, in which 

 position it is comparatively smooth. 



