PHENACODUS. 479 



small. Its distal extremity is cut off on the side next the M. ii, so that the 

 keel is near the inner edge. The internal edge is oblique. The first pha- 

 lange is rather elongate, The ungual has a round section near the base, and 

 the lateral edge is but little developed. The first phalange of the second 

 digit does not differ much from the corresponding piece of the posterior foot 

 except in its inferior .size. 



The distal extremity of the third metacarpal is somewhat contracted, 

 and does not have the flatness of that of the P. primcevus. Its posterior keel is 

 thick, and directed a little towards the thumb. The first phalange of the third 

 digit differs from that of the pes in its less depressed form and slightly reduced 

 length. The actual proximal depth is a little greater, while both extremi- 

 ties are distinctly narrower. Its distal ligamentous fossae are well marked. 

 The distal extremity of the fourth metacarpal is truncate on the inner side 

 and oblique on the exterior; the superior or anterior part of the condyle 

 being as narrow as in a carnivore, but not bounded proximally by the fossa 

 usually seen in that order. Keel distinct. 



The extremity of the fourth metacarpal is smaller than that of the sec- 

 ond. Its external epicondyle is more prominent than the internal. The 

 penultimate phalange is a little narrower than the corresponding one of 



the pes. 



Meastiremenfs of manus. ' u. 



( anteroposterior 009 



Diameters of trapezoi(les< c vertical 006 



^ anterior I j^^^g^gj^g ^053 



Distal transverse diameter of M. i 006 



Length of 1st xihalange of polles 008 



Length of M. ii 0352 



Distal diameters M.ii^"'^t'^'-°P°'^**"°'- OO'^ 



( transverse 0095 



Length of 1st phalange of M. ii 015 



Distal diameters M.iii 5 •^"^^^P''^*"'"'" ' "O^ 



( transverse 0082 



Length of Ist phalange of M. iii 018 



Proximal diameters of 1st phalange of M. iii J P 



C transverse 010 



Distal diameters of 1st phalange of M. iii ^™t«'•°P''«*«"°'■ 005 



(transverse 0072 



Distal width of M. iv 008 



The pelvis has an intermediate type of form. It has no resemblance 

 to that of a marsupial or a rodent, but resembles rather that of a carnivore, 

 as Canis and Ursits. It is in fact intermediate between that of those genera 



