14 BULLETIN 57, UNITED STATES NATIONAL MUSEUM. 
Among recent mammals the nearest approach to the conditions just 
described is found in the Colugidse. Here the trochiter and trochin, 
though less developed than in the Pteropidse, strongly suggests the 
form characteristic of the bats as compared with* their much more 
rudimentary condition in Tupaia. Of the two processes the trochin 
is distinctly the larger, and it is obvious at a glance that the distal 
extremity of the humerus in Cynocephalus more nearly resembles 
that of Pteropus than it does that of Tupaia or than that of P ter opus 
does the most highly developed type in the Microcliiroptera. This 
resemblance is further heightened by the size and form of the deltoid 
crest, which is rather closely alike in Cynocephalus and P ter opus, 
while in both Tupaia and the Microcliiroptera it is noticeably dif- 
ferent, At the distal extremity of the humerus the resemblance be- 
tween Cynocephalus and the bats is less exclusive. In the Colugidse 
both supracondylar foramen and supratrochlear perforation are 
present and the supinator ridge is well developed, characters all of 
which are in common with the Insectivora. The actual surface of 
articulation, however, resembles that of the bats in the reduction of 
the trochlea and the large size of the capitellum, the outer edge 
of which shows the first suggestion of the groove and ridge which is 
so prominent a feature in the Chiroptera. As would be expected 
from the reduced condition of the trochlea, the ulna is much reduced 
from its normal form. It is throughout very slender, the distal half 
flattened against radius, into which it blends near wrist. Proximally 
it is slightly larger than in Pteropus , though very greatly reduced as 
compared with Tupaia , and the small, abruptly curved olecranon 
forms a definite part of the joint, its extremity fitting into the supra- 
trochlear perforation. 
It seems, therefore, that without touching on the question of the 
general relationships of the Dermoptera, it may safely be said that 
the long bones and two principal joints of the anterior limb in this 
group are intermediate in structure between those of Insectivores and 
Bats, but distinctly nearer the latter, and that ill this respect at least 
Cynocephalus represents a stage that was passed through by the near 
ancestors of Pteropus. 
In 1892, Winge a first called attention to the striking differences, 
already alluded to, in the humerus and shoulder joint of the Mega- 
ehiroptera and of the more highly specialized Microcliiroptera. A 
fact not mentioned by Winge is that, while the Microcliiroptera, as a 
whole, show a much more specialized condition of the humerus than 
the Megachiroptera, different members of the group show different 
degrees of this modification, and these degrees are very largely charac- 
« Jordfundne og Nulevende Flagerinus (Chiroptera) fra Lagou Santa, Minas 
Geraes, Brasilien, p. 24, 
