1912] Miller: Pacific Coast Avian Palaeontology 67 
large size and high degree of pneumaticity. The latter character 
was considered by the author of the species as indicating the 
bird’s ability to fly. If such conclusion be true, the species, since 
the tarsometatarsus equaled in size that of the rhea, must be 
considered as the largest known flying bird. 
It may not be out of place here to consider the propriety of 
Cope’s position regarding the relation of pneumaticity to the 
power of flight. Let it be conceded that Cyphornis belonged to 
the Pelecanidae, birds of large size which are possessed of a 
high degree of pneumaticity. We may then ask if the char- 
acter pneumaticity necessarily became vestigial or disappeared 
with the loss of ability to fly resulting from increased size. The 
development of such a character as gigantism might be a matter 
of comparatively short time, while the persistence of the char- 
acter pneumaticity might be very tenaceous. An instructive case 
in point is that of Geococcyx, a cuckoo of terrestrial habit whose 
powers of flight have been almost entirely sacrificed. The pec- 
toral arch in this bird is an absurdly weak structure, while 
there is an accompanying accentuated development of the pos- 
terior limb region. Despite this inversion of the appendicular 
parts, the skeleton remains highly pneumatic. It seems well 
within the range of possibility that Cyphornis should have 
gained its large size by a rapid specialization—a tendeney run 
riot under certain conditions not adverse to it—and yet this 
specialization cost the bird its power of flight without blotting 
out the character of pneumaticity. 
Miocenr Fauna 
Mancalla californiensis Lucas, from the upper Miocene of 
Los Angeles, California, is described by Lueas’ as being much 
like the Recent species of murre (Uria troille) of that region, but 
more highly specialized in that it was probably without the power 
of flight. The single specimen known consists of the major part 
of the left humerus of a bird about the size of the recently 
extinct great auk (Plawrus impennis). Interest in this discov- 
ery lies largely in the strong similarity of the bird to Recent 
7 Lucas, F A., Proc. U. S. Nat. Mus., vol. 24, p. 133, 1901. 
