180 THI? CONDOR Vol. XVII There certainly is evidence of degeneracy of the eagle-like function of the foot. Let us examine the evidence. The points of attachment ot? muscles to bones are commonly marked by distinct roughnesses of very definite position. In a foot of great lifting powe.r, the attachment of those muscles which bend the leg at the tarsal joint are relatively far down the shaft of the tarsus, thus affording greater leverage for the lift. In like manner one grasps farther down on the pitchfork handle in lifting a heavier shock of hay. Wading, run- ning, and walking forms of birds employ the opposite method of attachment, sacrificing lifting power to gain distance of stride in the foot. To continue the homely comparison, the hay-maker shifts his hand back toward the end of his fork-handle after the weight has been raised and he wishes to gain distance for heaving his hay upon the load. Morphnus daggetti has similarly shifted his grip on ', his tarsal lever, or he has accomplished what is in effect the same, by an extreme elonga- tion of the shaft beyond the point of muscle attachment. This great long-shanked eagle has a power arm in his lever no longer than that of the Ferruginous Roughleg (Archib?- teo), although the resistance arm is almost twice as long as that of the same species. The Caracara (Polybor?s), who walks as readily as a turkey, has almost exactly the same relative position of its muscle attach- ment as has this great extinct eagle. The conclusion is unavoidable that the lifting power of the foot was extremely low. But what of the grasping power of his toes .? The three front toes of a bird are at- tached at the extremity of the tarsus to three articular surfaces known as trochleae. In the powerfully predaceous raptors these trochleae are deeply grooved and are set somewhat obliquely upon the shaft. Evi- dence of decline of the raptorial habit is seen in M. daggett.i in the fact that these Fig. 63. T?RSO?ET&T?US OF Mor?hnus tlaggetti (A? ?.?.r?) trochleae are more uniform, less deeply AnD Or Ardea herorlias; ? grooved, and are set less obliquely A?owr Two-??mos ?A?X upon the tarsal shaft. This condition is sxzE carried to its extreme in the Old World vultures which are conceded to be degenerate raptors, and is in marked contrast to the conditions in Aquila and Haliae?tus. The conclusion seems inevitable that this peculiar asphalt species was of more or less ambulatory habits--a bird which had forsaken the more actively predaceous manner of his aquiline an- cestry and lengthened out his shanks in much the same way, though perhaps not to the same degree, as has the Roadr, mner (Geococcyx) forsaken the tree- dwelling life of his cuckoo kindred to put on stilts. A condensed description of the new species is appended for the more tech- nical student. ?Iorphnu? d?ggetti, new species; type specimen, no. A-380, Los Angeles Museum of History, Science, and Art; a tarsometatarsus. Assignment of this
