IV.] 



SKELETON OF UPPER LIMB. 



167 



cannot be quite assumed by the adult human being, though 

 it is the permanent condition of some Reptiles, especially 

 the Chelonians. 



The head of the radius is often much larger relatively 

 than in man, as e.g. in the Dog and Ruminants. 



FIG. 142. RIGHT PECTORAL LIMB OF A GIRAFFE. 



CM, scaphoides ; rf 3 , proximal phalanx of third digit : d*, proximal phalanx of 

 fourth digit ; g, magnum ; gt, great tuberosity of the humerus ; /i, shaft of the 

 humerus ; lit, lunare ; &*, united metatarsals of third and fourth digits ; <?, 

 olecranon ; pi } pisiforme ; r, radius : sc, cuneiforme ; , unciforme. 



15. As with the radius, so with the ULNA, we can only 

 employ Vertebrates above Fishes for comparison. 



In the proportion it bears to the radius, man's ulna agrees 

 on the whole with the relation obtaining in the majority of 

 forms. 



It may, however, be larger and more important than the 

 radius, as is the case in Birds, e.g. the Eagle. On the con- 

 trary, it may be very much smaller and more or less abortive, 

 as in Ruminants and Bats. That the proportionate size of 

 this bone has no relation to flight is shown by the just- 

 mentioned fact, that it is the larger bone in Birds and the 

 smaller one in Bats. 



