A NEW MYLODON. 343 
tributary of the Osage River, Missouri. These were subsequently examined by 
Owen who considered them identical with M. harlani. Among the specimens 
are sixteen loose teeth, together with eight others in sockets, two humeri, 
portions of pelvis, sternum, and foot bones. At about the same time, Dr. H. 
C. Perkins described with some care a tooth and a humerus found twelve feet 
below the surface on the Willamette River, Oregon. For these remains, if 
belonging to an undescribed animal, he proposes the name Orycterotherium 
oregonensis (Amer. journ. sci., 1843, ser. 1, 44, p. 80, footnote). This humerus 
is now in the collection of the Boston society of natural history, but the tooth 
is lost sight of. Leidy (1855, p. 48) further confirms the identity of this bone 
with M. harlani. He describes a humerus from Big Bone Lick, Kentucky (the 
type locality) and states that its measurements accord with those of the Oregon 
specimen. This latter is much larger than that of the Nebraska Mylodon here 
described. It measures:— 
Greatest length, 510 mm. 
Greatest breadth across distalend, 285 
Width across distal condylar surfaces, 155 
Antero-posterior extent of same, 87 
Harlan in his account of the remains from Missouri gives the total length of a 
humerus as 20 inches (about 508 mm.), the breadth across the distal condyles, 
6 inches (about 152 mm.), which is quite in accord with the dimensions of the 
Oregon humerus. 
In the collection of the Museum of comparative zoélogy there is a fragment 
of the tip of a Mylodon mandible (Plate 4, fig. 16) labeled ‘“‘Walhaumet River, 
Oregon,” which, though it has no further history was evidently received many 
years ago, before the spelling ‘“‘ Willamette” for this river was adopted. The 
bone is stained a dark brown like the humerus from the same locality, and it 
is probable that it is from the same place or even from the same specimen. As- 
suming that it represents M. harlani, it supplies a portion hitherto undescribed, 
namely the predental part of the jaw. It includes the tip of the left ramus 
broken slightly to the right of the middle line of the symphysis, with at its pos- 
terior edge the basal part of the socket for the first tooth. It is clearly not 
referable to Paramylodon nebrascensis, in which the symphysis is considerably 
longer and narrower with a decided keel. From the Mylodon whose skeleton 
I have just described, it differs equally in the breadth of the truncate tip of the 
jaw, in the nature of the symphysis, and in the arrangement of the openings of 
the dental ‘canal. These last in the Oregon fragment consist of two large sub- 
