1912] Miller: Pacific Coast Avian Palacontology 93 
Haliaétus leucocephalus, and Geranoaétus melanoleucus. Aquila 
pliogryps Shufeldt is described from a single bone, the basal 
phalanx of the right hallux. The species is considered to be 
slightly larger but more slender-limbed than Aquila chrysaétos. 
The material representing the species is so limited that no clear 
impression of its closer relationships can be formed. Morph- 
nus woodwardi from Rancho La Brea may well have been such 
a bird, though there is no way of obtaining more than the sug- 
gestion of similarity from the facet that they were both eagles 
of slender build. The statement made by Shufeldt is that Aquila 
pliogryps was slender of foot, as indicated by the slightly longer 
digits. Morphnus is a genus of long-shanked eagles with rela- 
tively weak feet, as indicated by the size of the trochleae. The 
digits certainly must have been much smaller in Morphnus wood- 
wardi than in Aquila chrysaétos or in A. pliogryps. 
Shufeldt’s species, A. sodalis, is founded on the proximal 
part of a tarsometatarsus. The specimen is figured from the 
anterior aspect drawn to natural scale. Compared with the 
Rancho La Brea eagles, A. sodalis corresponds quite closely in 
size with Geranoaétus fragilis, the smallest of the group there 
represented. A. sodalis seems, however, to be of an entirely dif- 
ferent nature if the position of the papilla of the tibialis anticus 
may be taken as indicative. In a discussion of the splendid 
series of eagle tarsi from the asphalt, it has been pointed out 
by the author*’ that the position of this tubercle seemed to bear 
a very definite relation to the slenderness of the tarsus, i.e., the 
long-shanked forms have the tubercle placed high up on the 
shaft of the bone. Applying this principle to Shufeldt’s figure 
of A. sodalis, it would seem that the Fossil Lake species was 
not of the same group of eagles as the more southern genera 
Morphnus and Geranoaétus assembled by Ridgway under the 
caption Morphni. In A. sodalis the papilla of the tibialis anticus 
is placed farther down the shaft and the proximal foramina are 
separated by a much wider space. Unfortunately the charac- 
ter of the hypotarsus is not shown in Shufeldt’s figure of Aquila 
sodalis nor is an accurate impression of the region obtainable 
from the description. It seems proper to consider the two species 
27 Miller, L. H., Univ. Calif. Publ., Bull. Dept. Geol., vol. 6, p. 305, 1911. 
