5° 



NEW YORK STATE MUSEUM 



Passing to the tarsomctatarsus, we observe that among all of the 

 American vultures it has a tuberous hypotarsus, with a raised crest 

 extending from it below, that soon merges into the general sur- 

 face of the shaft upon the posterior aspect. In Cathartes this 

 hypotarsial process is sharply grooved in a vertical direction be- 

 hind. This is also the case in Catharista ; the King vulture has 

 the process broader transversely, the grooving shallower, with its 

 outer and posterior margins slightly produced. This condition is 

 still further advanced in the condors, while in Neophron we note 

 that it has been carried still further, so much so that the mid 

 vertical groove is now a broad concavity and the lateral productions 

 appear as separate and rounded processes. Its form is quite dif- 

 ferent in many of the Falconidae. Gypogeranus has the hypotarsus 

 very much as we find it in Cathartes a. septentrio- 

 nal i s . only rather longer for its width, which is what we might 

 expect in the skeleton of this bird of a stiltlike tarsometatarsus. .a 

 tough piece of cartilage is placed over this process in the Cathar- 

 tidae, through which several of the flexor tendons pass. The 

 summit of the tarsomctatarsus presents two lateral concavities with 

 a median anterior rounded tip, all for the accommodation, in the 

 articulated skeleton, of the trochleae of the tibiotarsus. 



Horizontal sections made at almost any point of the shaft are 

 more or less parallelogrammic in outline, and this portion of the bone 

 is markedly straight in all of these vultures, for we know that in 

 many of the Falconidae. and the condition is slightly observable in 

 Xeophron. that the tarsometatarsus is often more or less bent in the 

 reverse direction of the tibia above. Upon its anterosuperior sur- 

 face the shaft of the tarsometatarsus is very much scooped out in 

 the longitudinal direction. Two foramina pierce the shaft at its 

 upper part, and one of them appears upon either side of the hypo- 

 tarsus posteriorly. Distally. the shaft is pierced anteroposteriorly 

 by the large foramen for the anterior tibial artery, the aperture 

 occupying its most usual site. The three trochlear processes that 

 project from this bone distally arc large and well separated from 

 each other, the mid one being the largest, standing out in front of 

 the others and possessing a very decided median grooves that passes 

 clear round its entire surface : this feature is usually absent on the 

 lateral processes, of which the outer is the smaller: these are placed 

 slightly to the rear of the middle one. particularly in the condors, 

 least of all in Catharista. in which vulture all three are nearly in the 

 same transverse plane. The concave facet for the os mctatarsaJc 



