SINCLAIR : TYPOTHERIA OF THE SANTA CRUZ BEDS. 
59 
distally. Those of the first row have the distal articulations confined to 
the distal and palmar surfaces, while in the second row the distal surface 
is in part dorsal, indicating some angularity in the position of the digits 
(PL IX). The terminal phalanges are laterally compressed hoofs, some- 
times with slight terminal clefts. 
Restoration . — The restored skeleton (PI. IX) shows to advantage the 
large head, long back, heavy tail and short limbs. A digitigrade gait is 
inferred for the same reasons as those already given (p. 33) in discussing 
the gait of Protypotherium. 
Interatherium robustum (Ameghino). 
(Pis. VI, Figs. 11, 12, 16-20; VIII, Figs. 2, 5-8, 10-16, 19, 26, 29, 30 ; IX ; 
Text Figs. 1 B, 1 1.) 
Icochilus robustus Amegh.; Revista Argentina de Hist. Nat., I, p. 393, 
footnote, fig. 97, but not figs. 95 and 96, 1891 ; Segundo Censo, etc., 
p. 150, fig. 17, 1898 (listed). 
Characterized by the presence of a large persistent I-, 
and curved fronto-nasal suture. The temporal ridges are 
acutely convergent and not lyrate as in I. excavatum. 
The following localities have afforded specimens of this 
species : Ten miles south of Coy Inlet (5), five miles south 
of Coy Inlet (1), eight miles south of Coy River (1), Coy 
Inlet (1), Killik Aike (1), seven miles south of Mt. Leone 
(1), Canon de las Vacas, thirty-five miles south of Santa 
Cruz (nodule layer) (1), Canon de las Vacas (2), Felton’s 
estancia, Rio Gallegos (1), Halliday’s estancia, Rio Galle- 
gos (1), Rio Gallegos (1), Monte’s Casa, seven miles south 
of Coy River ( 1). 
As in the preceding lists, the figures in parentheses indi- 
cate the number of specimens from each locality. 
Nos. 15,401, 15,100, 15,348 15,293, and Nos. 9129 and 9263 of the 
American Museum collection are illustrated in the accompanying plates. 
Measurements. 
No. 
No. No. 
No. 
9263. 
15,34.8. 15,100. 
I 5 > 40 i. 
Skull, length premaxillse to inion 
.082 
•0735 
.080 
“ greatest width across arches . 
b 
Cn 
00 
.0505 
.0585 
“ interorbital width .... 
. 
.031* 
* Approximate. 
Fig. 11. 
Interatherium 
robustum , show- 
ing the curved 
fronto-nasal su- 
ture, x y (No. 
15,300). 
