1894.] 247 [Scott. 



The proximal articular surface is more deeply concave, and more 

 oblique to the long axis of the bone, presenting dorsally as well as proxi- 

 mally. (3) The dis- 

 tal trochlea is less 

 depressed, more 

 deeply notched and 

 extends farther upon 

 the palmar side. In 



the second phalanx "Pi a '\ 



the dorso-palmar di- o* 



ameter is relatively Fig- 3. Pbalauges of iv digit of manus. Same individual 

 much greater and the ^' ^'S'- ^ """^^ ~' '^^*- '^="^- 



transverse diameter less than in Oreodon. The median ridge of the prox- 

 imal trochlea is much more prominent and the lateral concavities of this 

 surface more deeply excavated. The distal articular facet is much more 

 extensive, especially upon the palmar side, and more deeply notched 

 in the middle line. The ungual is compressed and forms a large claw, 

 quite unlike the slender pointed hoof of Oreodon, though the difference is 

 hardly a fundamental one. The facet for the second phalanx is much 

 greater in the dorso-palmar direction and allows a more extended move- 

 ment of the two bones upon each other. The mutual relations of the 

 three phalanges is quite different in the two genera; in Agrioch(e,rus the 

 arrangement is much like what is found in Chalicotheriiim. 



The tibia differs in several important respects from that of Oreodon. 

 The proximal end is carnivorous rather than ungulate in appearance. 

 This is due partly to the flatness of the condyles and their slighter obliquity 

 from before backward, but especially to the small prominence of the 

 cnemi>il crest, which though broad and massive is much lower than in 

 Oreodon, and hence the proximal portion of the tibia has a decidedly 

 smaller anteroposterior diameter than in that genus ; the spine is also 

 less conspicuous. The di«tal end is remarkable for the great size of the 

 internal malleolus, which is very long and has an articular facet for the 

 astragalus upon its free end. 



The tarsus has already been fully described by Osborn and Wortman. 

 It is requisite here, therefore, only to call attention to the differences 

 which obtain between the various species of Agrioclioerus, as well as be- 

 tween the latter genus and Oreodon. In the absence of teeth it cannot 

 yet be determined whether the specimen described by Osborn and Wort- 

 man should be referred toany of Leidy's species and therefore, for the pur- 

 poses of the present comparison, the name A. gaudryi O. and W. will be 

 retained. A. antiquus from tlie Oreodon beds differs from A. gaudryi ia 

 the following particulars : (1) The size is somewhat smaller. (2) All the 

 elements of the tarsus are relatively higher and narrower. (3) There is 

 less difference in size between the internal and external condyles of the 

 astragalus and the latter is separated by a much wider interval from the 

 cuboidal facet. (4) The pit for the internal malleolus is much less deeply 



PUOC. AMER. PHILOS. SOC. XXXIII. 145. 3 F. PUINTED JUNE 19, 1894. 



