144 THE DESEADO FORMATION OF PATAGONIA 
in the lower series. The Deseado forms are also of con- 
siderably larger size than the Santa Cruz. 
Our material includes a pair of lower jaws, two scap- 
ulae, the humerus, and the lower end of the femur. — 
No skull has been found in the Deseado. Those from 
the Santa Cruz are enormously swollen over the orbits, 
the massive bone making a skull wholly unique. The 
lower jaws are similar to those of Astrapotherium, except 
that the rami are deeper. The front ends are fused and 
expanded making the anterior much enlarged, and causing 
the incisors to stand at intervals as in Coryphodon. ‘The 
symphysis is massive and prolonged backward nearly to 
premolar 3. The rami are plump and unusually thick. 
Fig. 102. Upper dentition of Astrapothericulus iheringi— 
1/2 natural size. 
Of the upper dentition, Ameghino figures only the first 
molar and the canine. I have given Ameghino’s figure 
of the upper dentition of Astrapothericulus, to indicate 
what this would be like, for the variation is only slight. 
The canine is a great tush, not unlike the incisor-tush of 
Pyrotherium, oval in cross section with the greater diameter 
from front to back. The first and second premolars have 
disappeared. Premolars 3 and 4 are greatly reduced. 
The molars are very like those of Asmodeus, large brachy- 
dont grinders, composed of an outer wall, and an anterior 
and posterior lobe. The external cingulum is a_ trace 
only, and the internal cingulum is developed in varying 
degrees. The basin is deep and subdivided by a crista 
which rises from the external wall, and as the surface is 
worn off unites with the anterior lobe, cutting off a small 
