503 



of the distal trochlea is less produced than in Procoptodon Eapha, and the whole hind 

 surface of the joint is less obliquely disposed than in that species or in Procoptodon 

 Pusio. 



Thus the resolution of these shorter and stouter metatarsals into three categories, 

 characterized by modifications of shape as well as by size, concurs with the previously 

 adduced evidences of jaws and teeth in showing that the procoptodont modification of 

 Macropodida? was of old manifested by Australian Kangaroos under three specific forms. 



But these, which my present materials have enabled me to define, may prove not to 

 have been the only links connecting the saltigrade with the gravigrade groups of 

 phytiphagous Marsupials. 



Fig. 1. Front view of right humerus. 



Fig. 2. Back view of the same. 



Fig. 3. Inner side view of the same. 



Fig. 4. Outer side view of the proximal end of the same. 



Fig. 5. Proximal articular end of the same. 



Fig. 6. Distal articular end of the same. 



Description of the Plates. 



PLATE CXI. 



Phascolagus alius. 



PLATE CXII. 



Macropus Titan. 



Fig. 1. 

 Fig. 2. 



Front view of the right humerus. 

 Side view of the right humerus. 



PLATE CXIII. 



Macropus Titan. 



Fig. 1. 

 Fig. 2. 

 Fig. 3. 



Oblique view of the proximal end of the right humerus. 



Proximal articular end of the same. 



Back view of the proximal end of the same. 



Undetermined Species. 



Fig. 4. 

 Fig. 5. 

 Fig. 6. 



Front view of the distal end of the right humerus. 



Back view of the same. 



Distal articular end of the same. 



