SCOTT: ENTELONYCHIA OF THE SANTA CRUZ BEDS. 285 
one-eighth, which is well within the ordinary limits of individual varia- 
tion. It is probable, therefore, that there is no substantial difference 
in size between the two species. 
In the original description the following dimensions are given : length 
of skull from incisors to occipital condyles, inch, .400; maximum width, 
.250; length of upper dental series, .210; breadth of palate at m-, .061. 
In the imperfect young skull (No. 16,014) which I have, with some 
doubt, referred to this species, the almost unworn m- measures 45 mm. 
in antero-posterior, by 40 mm. in transverse diameter. 
Localities. — For the type, none is given, and the field-label of No. 
16,014 is unfortunately lost, but the specimen almost certainly came 
from the Atlantic coast near Coy Inlet. 
Homalodontotherium excursum Ameghino. 
Homalodontotherium excursum Amegh.; Enum. synopt. des especes de 
Mamm. Foss, des Formations Eocenes de Patagonie, 1894, p. 64. 
This is the smallest of the known Santa Cruz species, as appears from 
the comparative measurements which Ameghino gives in the original de- 
scription and may be thus tabulated : 
H. segovice. H. excursum. 
Astragalus, length .......... .084 
width .......... .062 
Tibia, proximal width 135 
.074 
•054 
.100 
Localities. — Not given. 
Homalodontotherium crassum Ameghino. 
(Plate XXX, Figs. 5, 5a, 56.) 
Homalodontotherium crassum Amegh.; Enum. synopt., etc., p. 64. 
Ameghino has distingushed this species on the ground of its very 
large size, “taille gigantesque,” though only a few foot-bones have been 
found. His measurement are as follows : 
H. segovice. H. crassum. 
Metacarpal III, distal width ........ .036 .042 
Unciform, length .......... .049 .066 
“ width 057 .072 
thickness .......... .034 .050 
