FLESH-EATING MAMMALS. 51 



part of the globe, and there is, in consequence, practically no limit to tho 

 range over which a species may extend itself ; while being dominant forms, 

 the number of species in a genus has naturally multiplied to a great extent. 

 As might be expected in such a case, the different species of many large 

 genera display a marked tendency to variation, so that there is frequently 

 much difficulty in deciding as to what constitutes a species, and what a mere 

 variety ; this being remarkably exemplified among the great groups of the 

 cats and foxes. 



Although certain extinct forms, of which no further mention will be made 

 in this volume, tend to connect them with the Insectivora, the modern Car- 

 nivora form a tolerably well-defined group, which would, however, be easier 

 of definition were the seals and walruses referred to a separate order. 

 Throughout the group the number of toes is very generally five, and never 

 falls below four on each foot ; and in all cases these toes are armed with 

 claws, which are usually curved and sharp, and bear no resemblance to nails. 

 Neither the equivalent of the thumb or the great toe of the Primates can be 

 in any way opposed to the other digits. Very frequently collar-bones are 

 wanting, and in no instance are they complete ; that is to say, they never 

 connect the blade-bone, or scapula, with the breast-bone, as they do in the 

 Primates and Insectivora (except the Potamogalidce). The teeth, which are 

 divisible into the ordinary four series, are generally well-developed ; the 

 number of incisors being usually three on each side of both jaws, and the 

 outer pair, especially in the upper jaw, is considerably longer than either of 

 the other two. The canines almost invariably form large tusks ; and the 

 more anterior, or the whole of the cheek-teeth have compressed and pointed 

 crowns, frequently consisting of one large central cone, supported by a 

 smaller cusp in front and behind. In the terrestrial Carnivora the last 

 premolar in the upper, and the first molar in the lower jaw, are 

 specially modified to bite against one another with a scissor-like action, 

 and are accordingly spoken of as the carnassial, or sectorial teeth. 

 These teeth attain their maximum specialisation and perfection among 

 the cats : whereas in the bears and some of the raccoon family their 

 sectorial character is much less marked, although it is still noticeable. On 

 the other hand, in the seals and walruses all the cheek-teeth are nearly alike, 

 and are generally cusped and sharp -pointed throughout the series, although 

 blunt in the latter family. The modification of the limbs into flippers affords, 

 however, an easy method of distinguishing the whole of the seal group from 

 other Mammals. As a rule, when the number of cheek-teeth is reduced below 

 the normal, the reduction takes place at the hinder, or molar end of the series, 

 whereas in most other Mammals it is the anterior premolars that tend to 

 disappear. 



In the skull of all Carnivores the lower jaw is articulated by a transversely- 

 extended sub-cylindrical condyle, clasped in front and behind by two over- 

 lapping processes from the skull itself, which are sometimes so prominent as 

 (in the badger) to prevent the dislocation of the lower jaw without fracturing 

 the bone. Very generally, the socket of the eye is freely open behind, al- 

 though in certain cats and the mungooses it is surrounded by a complete bony 

 ring. The zygomatic arch, so frequently absent in the Insectivora, is almost 

 invariably well developed in the present order. A peculiarity in the wrist- 

 joint of all the Carnivora is that the two bones known as the scaphoid and 

 lunar, forming the inner and upper elements of the upper row of this part 

 of the skeleton in other Mammals, are here fused together to form but a 



