yv. 1 MARSUPIALIA. 253 



broad, and remarkable for the great development of the 

 points of muscular attachment, as the tuberosities, deltoid 

 and supinator ridges, and internal condyle. These all reach 

 their maximum of development in the Armadillos, animals 

 which make great use of their fore-limbs in scratching and 

 burrowing. The supracondylar foramen is present in all. 



The radius and ulna are also well developed and distinct 

 in all, but with no great amount of motion permitted 



Ietween them. The olecranon is always long and strong. 

 Order Marsupialta. — In the burrowing Wombat (Phasco- 

 miys) the humerus is stout, very broad at the lower end, 

 nd with strongly developed deltoid and supinator ridges 

 (See Fig. 81, p. 242.) These characters prevail generally 

 throughout the order, though in a less maiked degree. The 

 supracondylar foramen is almost always present, some of 

 the Dasyures being exceptions. 



The radius and ulna are always distinct and well-developed 

 bones. The upper end of the radius is small and rounded, 

 and more or less rotation is permitted between the bones, 

 n in the carnivorous forms. 



In both the genera of animals constituting the order 

 Monotremata, the humerus is something like that of the 

 Mole, short and extremely broad at both extremities, with 

 greatly produced inner and outer condyles, though con- 

 tracted at the middle of the shaft. 



The radius and ulna are stout, and rather flattened at the 

 lower end, where they are of about equal size, and closely 

 applied together. The upper end of the olecranon is 

 widely expanded laterally. 



