THE CANID^E, OK DOGS. 275 



gentle modifications to Mustela, and henceforth 

 there exist weasels. 



Equally distinct are the intermediate forms 

 by which is accomplished the transition from the 

 weasel's dentition to that of the Cats. The genus 

 Procelurus appears likewise with two tuberculate 

 teeth in the upper jaw behind the carnassial tooth. 

 But single species of the genus sometimes show a 

 loss of the back molar, and herein approach the 

 cats ; the back edge of their carnassial tooth, more- 

 over, loses a tubercular heel or process. By this 

 small modification Protelurus has become Pseud- 

 celurus, inasmuch as the modification was general and 

 continued for some length of time. In comparing 

 the following statement of the simplification of the 

 molars of the lower jaw : 



Premolars Carnassial Tubercular teeth 

 4 1 lp t m 2 



4 1 0pi m, 



3 1 0^3 w, 



which have actually been observed, and which 

 shows, moreover, that the front premolar p 2 has 

 also become reduced it becomes clear that the only 

 distinction between a Pseudalurus of this kind, for 

 example, Ps. Edwardsii and our present cats, is that 

 it possesses a minute premolar. Hence the great 

 simplification in the number of teeth which Filhol 



