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 tendency 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. 



MIOCENE FAUNA 



Mancalla calif or niensis Lucas, from the upper Miocene of 

 Los Angeles, California, is described by Lucas 7 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 (Plaurus 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. 



