1 88 BRITISH MAMMALS 



in one genus of Machairodonts, while a tendency towards loss of 

 the lower incisors is beginning in the weasels. 



The true molar teeth in the seals are tending towards 

 disappearance. They are paltry in size and development, and 

 often reduced to mere rounded stumps. They are never more 

 in number than two pairs in the upper jaw and one pair in 

 the lower. The premolars are larger in size than the molars 

 (usually), and, like the last-named, are simple, narrow, three- 

 cusped teeth (where they are not reduced to rounded stumps or 

 mere cones). It would seem to be impossible, having regard 

 to the structure of the teeth, to derive the seals from the bears 

 or the otters, or from any other form of existing land Carnivore. 

 On the other hand, the teeth do offer some slight resemblance 

 to those of the Creodont Carnivores, such as, for instance, those 

 of the family Palaonictida. This family contains one genus 

 (Patriofelis) which presents a similarity to the seals in the con- 

 struction of its feet, though it is more differentiated in its 

 reduced premolar teeth. In the vertebrae the seals are more 

 related to the Creodonts. The alisphenoid canal is present in 

 several examples of the Pinnipede, and is also present in most 

 of the Creodonts. It is absent from the otters, though it is 

 present in the bears, the dogs, and some other Fissipedes. A 

 remarkable resemblance to the Creodonts exists in the formation 

 of the astragalus (one of the ankle bones). The special re- 

 semblances which the seals offer to the bears and to the otters 

 consists in the lobulated kidneys, and in that portion of the brain 

 called the " ursine lozenge," which rises in the middle of each 

 hemisphere. But another point in which the seals differ markedly 

 from the whole group of bears, weasels, otters, etc., is that in the 

 latter there is no caecum, or blind gut appendage, to the alimen- 

 tary canal, whereas a caecum exists (even though it be very short) 

 in all the seals. All seals are described by biologists as having an 

 extremely short tail. It would be more correct to say that the 

 external tail is reduced to a stumpy lump or tuft ; but there are 

 a fair number of caudal vertebrae remaining, so that the seal is 

 really a creature with a moderately short tail, the bony part of 



