320 A NEW MYLODON. 
nebrascensts. Of the first, Owen’s classic memoir (1842) treats in detail, and the 
Museum possesses a mounted skeleton from the Pampas formation of Argentina. 
No complete account of the North American WV. harlani has been published, and 
since the type consisted of but a portion of the lower jaw with the teeth, some 
doubt attaches to the identification of other fragments of the skeleton later 
referred to the same species. Cope (1895) first described and figured what 
are doubtless the upper teeth of this animal, and Leidy and others have described 
and figured bones which are believed likewise to represent it. No complete 
skull seems to have been found, but Cockerell in 1909 published an account of 
a cranium without teeth from Colorado which, after careful comparison of photo- 
graphs, I believe is identical with MW. harlani. To the same species are probably 
referable the teeth on which Cope founded Mylodon renidens and M. sulcidens, 
names currently included in the synonymy of M. harlani. Cope’s Mylodon 
sodalis, based on an ungual phalanx, remains unknown. ‘The description of 
M. garmani follows. 
The skull (Plates 1, 2) except for the loss of a few chips here and there, is 
practically perfect and is clearly that of an adult animal. In general outline it 
resembles that of other species of Mylodon, but is extremely narrow. The dorsal 
profile is a nearly straight line with a slight depression above the orbit (in the 
specimen the actual depression is accentuated through a slight crushing in of the 
skull). The palatal profile is nearly parallel with the general dorsal outline but 
its plane if produced backward, would pass nearly through the center of the 
occipital condyles, as in Paramylodon. The pterygoids extend downward 
from the palatal plane to a distance about equal to one half the height of the 
braincase. The rostrum in side view is abruptly truncate, its general outline 
nearly at right angles to the dorsal profile. The upper half is convex, the lower 
half nearly vertical, or slightly concave, thus resembling Cockerell’s specimen 
from Colorado, here considered M. harlani, but differing from Paramylodon, in 
which the lower half extends gently forward and downward. The maxillae 
and premaxillae extend some 80 mm. in advance of this boundary. The pos- 
terior profile of the skull is gently and evenly convex, beginning at a point on the 
dorsal margin directly above the posterior base of the squamosal process. Its 
curve if continued passes through the posterior third of the occipital condyle, 
thus more as in Paramylodon than in the Colorado skull whose condyles lie 
mostly outside the posterior outline of the cranium. 
In dorsal view, the most striking character is the extreme narrowness of 
the braincase, whose greatest breadth, measured at the junction with the 
