382 PALAEONTOLOGY 



The fore foot of the ox is reduced to two principal toes, 

 with two rudimentary oues dangling behind. Each of these 

 has its extremity enveloped by a thick horny case, or hoof ; 

 this modification is accompanied by a junction or coalescence 

 of the radius (n) and ulna (w), preventing reciprocal rotation 

 or movement of those bones on each other ; by a joint 

 restricting the movement of the fore arm (antibracliium) upon 

 the arm (brachium or humerus, h) to one plane ; by a long and 

 narrow blade-bone (s), with a stunted coracoid and no clavicle ; 

 in short, by modifications adapting the limb to perform the 

 movements required for locomotion, and almost restricting it to 

 such. This type of fore limb is always associated with broad 

 grinding teeth, and with the modifications of jaw and skull 

 above defined. The due amount of observation assured Cuvier 

 that these several modifications, like the contrasted ones in 

 the Carnivora, were correlated, and he enumerates the physio- 

 logical grounds of that correlation. 



These grounds may be traced to a certain degree in the 

 secondaiy modifications of the carnivorous order. If the 

 retractibility of the claw be suppressed, the carnassiality of 

 the teeth is reciprocally modified. If the unguiculate foot is 

 reduced from the digitigrade to the plantigrade type, the 

 dentition is still more altered, and made more subservient to 

 a mixed diet. 



By the application of the correlative principle to the fossil 

 mammalian remains of pliocene and later deposits, the Her- 

 bivora have been distinguished from the Carnivora ; and out 

 of the latter have been reconstructed extinct species of the 

 feline, viverrine, ursine, and other families of the order. In 

 England and continental Europe a peculiarly destructive 

 feline quadruped existed, with the upper canines much elon- 

 gated, trenchant, sharp-pointed, sabre-shaped, whence the 

 name Machairodus proposed for this feline sub-genus. It was 

 represented by species as large as a lion (M. cultridens and 



