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 

 orexjonensis (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 

 specmien. This latter is much larger than that of the Nebraska Mylodon here 

 described. It measures: — 



Greatest length, 510 mm. 



Greatest breadth across distal end, 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 zoology 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 tlie 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- 



