284 
PATAGONIAN EXPEDITIONS I PALAEONTOLOGY. 
The femur of somewhat doubtful reference, belonging to the La Plata 
Museum and described above, yields the following measurements : 
Femur, length fr. head . . . .536 Femur, width over 3rd trochanter . .128 
“ “ “ gr’t trochanter . . .518 “ distal width 12 1 
proximal width. . . . .173 “ “ thickness . . . .101 
In the Ameghino collection are the distal ends of a tibia and fibula, of 
which the approximate dimensions, measured from photographs, are here- 
with given and, for comparison, those of an isolated distal moiety of a 
tibia (No. 15,435) in the Princeton Museum. 
No. 15435. Amegh. 
Tibia, distal width, inch tubercle ....... .099 .088 
“ “ “ excl. “ 089 .079 
“ thickness, int. border ....... .046 .042 
“ “ “ ext. “ 015 
Fibula, width of shaft ......... .024 
“ distal width, inch tubercle .058 
“ “ “ excl. “ .052 
“ thickness ......... .055 
Localities. — The type of the species was obtained by Dr. R. O. Cun- 
ningham from the cliffs of the Rio Gallegos. The specimens collected 
by Messrs. Hatcher and Peterson were found on the Atlantic coast in the 
neighborhood of Coy Inlet. Ameghino and Lydekker assign no localities 
for the individuals described by them. 
Homalodontotherium segoviae Ameghino. 
(Plates XXVIII, XXIX, Fig. 2; XXX, Figs. 1, 2, 4, 7.) 
Homalodontotherium segovice Amegh.; Rev. Argent, de Hist. Nat., T. I, 
1891, p. 295. 
This probably valid species differs from H. cunninghami chiefly in the 
narrowing of the muzzle, the smaller incisors and much reduced first 
upper premolar (p x ). The development of the cingulum and the larger 
canines, upon which stress was laid in the original description, are too 
fluctuating to have taxonomic significance. In a later publication Ame- 
ghino mentions merely the difference of size, saying that H. segovice is 
“one-third smaller than” H. cunninghami (’98, 172). It is difficult to 
know precisely what is meant by this vague expression. In linear dimen- 
sions the difference between the types of the two species is only about 
