206 DIVISION OF CARNIVORA INTO FAMILIES. 



size would make their resistance formidable, or whose swiftness 

 would give them a good chance of escape from direct pursuit. 

 But when they have made their spring, the claws are caused to 

 project, by the action of the muscle just mentioned ; and they 

 are then used to seize and tear their prey, for which purposes 

 their strength, sharpness, and curved form render them very 

 efficient. The movement here described may be readily observed 

 by every one, in the foot of the Domestic Cat. 



1 85. The division of this order into families is chiefly based upon 

 the conformation of the teeth and extremities, which here afford 

 very constant and distinct characters, and are closely connected with 

 the general structure and habits of the animals. 1 . FELIDJE, or 

 Cat tribe ; this is evidently the typical family of the order, being 

 the one in which the carnivorous propensity is most strongly 

 manifested, and in which the instruments of destruction are most 

 completely adapted for its exercise. The family is characterised by 

 the short powerful jaws, the digitigrade extremities, the retractile 

 claws, and the peculiar adaptation of the teeth for cutting. The 

 dentition is as follows ; incisors -|, canines ^, false molars |j|, 

 carnivorous molars J^, tuberculated molars ~. The canines are 

 of great size and strength ; the molars have sharp edges, the car- 

 nivorous tooth is very large and sharp, the tuberculated molar 

 behind it very small in the upper jaw, and not at all developed 

 in the lower. 2. MUSTELID^E, or Weasel tribe ; these are dis- 

 tinguished by their long narrow bodies, and by their propensity 

 to suck blood, rather than to devour flesh ; they are mostly 

 semi-plantigrade, a portion of the sole touching the ground, espe- 

 cially in the hind feet ; and their dentition is as follows ; incisors 

 j|, canines |^, false molars |^, carnivorous tooth ^, tubercular 

 molar (small) J. Thus we see that they approach the Felidse 

 in their dentition, as they do in their sanguinary habits. 3. The 

 CANID^:, or Dog tribe; the animals of this family are digitigrade, 

 like the Cats, but their claws are not retractile ; their carnivor- 

 ous propensity is not so strong ; the jaws are more elongated ; 

 and the dentition is as follows ; incisors -f , canines i^, false 

 molars , carnivorous molars ^, tuberculated molars | . 



