314 



FOUNDATIONS OF BIOLOGY 



most similar among living Mammals to the generalized or 

 focal type of terrestrial Mammal. Gymnura has relatively 

 short pentadactyl limbs with the entire palms and soles 



Cursorial- Volant 



Unguhgrade Aerial) 



Cursorial-Digitigrade 

 (Terrestrial) 



Scansorial 

 (Arboreal) 



Ambulatory 

 (Terrestrial) 



Natatorial 

 (Amphibious) 



Short-limbed, plantigrade, 

 pentadactyl, unguiculate 

 stem 



Fossorial 

 (Subterranean) 



(Aquatic) 



FIG. 161. Diagram of the adaptive radiation of Eutherian Mammals as exhibited 

 in limb structure. (From Lull.) 



resting flat upon the ground (PLANTIGRADE) and therefore 

 essentially adapted for comparatively slow progression. 

 (Fig. 162.) 



Radiating from this focus, adaptations for rapid running 

 (cursorial adaptations) are chiefly evident in a lengthening 



