THE 



AMERICAN NATURALIST. 



Vol. XXXVIII. January. ig04. 



ADAPTATIONS TO AQUATIC, ARHORKAL. FOS~ 

 SORIAL AND CURSORIAL HABITS 

 IN MAMMALS. 



IV. ClKSOKIAl. AnAI-TATloXS. 



R[CII.\RI) .S\VA.\.\ lA I.I,. 



Of all portions of an animal's body to undcr<,o) specialization, 

 those which have to do with locomotion show ])erhaps the most 

 varied adaptations. Speed is so essential to a <(reat number of 

 forms, either for escape from the enemy or lor the chase of prey, 

 that its degree of development has much to do with the fitness 



the modifications undericone by the feet and liml)s, and to a less 

 extent in the Ien^nhenin,i;- of the head and neck in Ion- limbed 



shown in the mouldin<4- of the contour of tlie body to losen the 



in saltatorial forms an increase in the len-th and wei-ht of the 



Most terrestrial mammals can run ; l)ut in comjiaratively few 

 orders is there any special adaptation for speed. ( )ffensive 'fli-ht 



