THE OSTEOLOGY OF SINOPA— MATTHEW. 



227 



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Tibia andfihula. — The proportion of these two bones is about as 

 in Hyxnodon^ the fibular shaft less reduced tlian in modern carnivora, 

 among- which the viverrines offer the nearest approach, while Dapftmius 

 is decidedly nearer. The bones are proportionately shorter, with less 

 rounded shafts than in the more modernized carnivora, e. g-., Canis or 

 Fdis. The most marked 

 peculiarity is the well- 

 deyeloped tibulo-calcanear 

 facet, which is onh' a little 

 less extensiye than in 

 IJyxnodon. 



Hind foot. — The pes is 

 pentadactyle, and its sym- 

 metry is approximately 

 mesaxonic, but less ex 

 actly so than in the manus, 

 the tirst digit being 

 shorter and more slender 

 than the lifth, and the 

 second somewhat shorter, 

 although stouter, than the 

 fourth, while the third 

 projects beyond either, 

 and is nearly, but not 

 quite, symmetrical at its 

 distal end. This symme- 

 try agrees entirely with 

 that of Hyaenodon and dif- 

 fers radically from the par- 

 axonic sy mmetr}^ of manus 

 and pes in the true Carni- 

 yora and the Meson3xhid{e, 

 In the Oxyfenidae the foot 

 symmetry appears to be 

 approximately as in the 

 Hyjenodontids, but the 

 foot is broader and shorter, 

 especialh' in PatriofeUs., 

 and the symmetr}- less no- 

 ' ticeable in consequence. 



The astragalus differs considerably from that of Hycenodon. The 

 trochlea is not nearly so deep, the posterior tendinal grooye is much 

 deeper, the neck is longer, the head much broader, not nearly so deep, 

 more convex laterally. The astrag-alar foramen is distinct, but very 

 small, and I cau not be certain that it is continuous through the bone. 



Ul 



Fig 



19.— SiNOPA r;RAN(;ERI, tibia and fibula, NAT. SIZE, 

 ANTERIOR AND POSTERIOR VIEWS. «t, CNEMIAL CREST ON 

 ANTERIOR SURFACE OF TIBIA; i. TO., INTERNAL MALLEOLUS 

 OF TIBIA. 



