464 DE. H. W. MAKETT TIMS Olf THE 



Cope, in his paper " On the Mechanical Origin of the 

 Sectorial Teeth of the Carnivora" (2), remarks "it is well known 

 that in the evolution of the sectorial dentition of the Carni- 

 vora the number of molars and premolars has considerably 

 diminished." 



It has been said (4), in connection v;ith the primitive dentition 



of Otocyon, that " there is at present no palseontological proof 



of this, as none of the numerous fossil forms of Canidse yet 



discovered have more than the normal number of molars." I 



M ould point, in answer to this, to such a form as the Oligocene 



3143 

 DapJicenus ^ith a dental formula g i ^ .. =44, which, according to 



AV. B. Scott (24), is in the direct line of ancestry of the Dog. 

 This genus differs from the specimens of Otocyon^ with the single 

 exception above referred to, in the loss of one lower molar only. 

 If we look at all the members of the Carnivora in which the 

 number of molars is not equal in both jaws, it will be seen that 

 the number is always greater in the lower jaw, from which one 

 might infer that the upper molars were the first to und';rgo 

 numerical reduction ; and from this it follows that, given an 

 equal number of true molars in both jaws, if any teeth have 

 undergone suppression, the last tooth to have been suppressed 

 would be in the lower jaw. If this inference be allowable, then 

 we may presume that one of the more immediate ancestors of 

 Daphcenus had an additional lower molar, the loss of which 

 alone distinguished it from Otocyon. 



That the Canidae very early acquired a reduced dentition is a 

 fact, and it is, I think, in accordance with their great number 

 and wide distribution both at the present time and in past ages ; 

 and, conversely, the retention by Otocyon of a primitive dentition 

 agrees with its restricted area of disiributiou, one species 

 (0. megalotis) only being known. 



Prom these considerations I am the more inclined to the 

 opinion that in Otocyon we have to do with a form in which 

 a very primitive numerical condition of the teeth has been 

 retained. 



Description of the Permanent Teeth of Otocyon megalotis. 

 Upper Jaw. — The first and second incisors are very similar to those of the 

 Dogs generally. Between the i.^ and i.^ is a slight diastema. 



The third incisor is somewhat larger than the others. It has a cingulum on 



