262 THE INCISORS OF SCEPARNODON. 



inference is that their companions are the corresponding lower 

 teeth. 



The inference can only be evaded by attributing them to another 

 species. To effect this we shall have to suppose either that we 

 know only the upper teeth of one species and the lower of another, 

 a supposition which its responsible originator will have to recom- 

 mend by the doctrine of chances, or that the second species had 

 abnormally long working surfaces on its upper incisors and corre- 

 spondingly enormous elongations of those surfaces on the lower 

 incisors. The probability of this condition of things it is hardly 

 necessary to discuss. 



It must be concluded that both the upper and lower incisors of 

 Scepamodon are known, and, consequently, that Scepamodon is 

 not a synonym of Phascolonus. 



EXPLANATION OF PLATE xxn. 



Scepamodon ramsayi, Ow. 

 Fig. 1. — Right upper incisor, adult. 

 Fig. 2.— Right lower incisor, young. 



