326 



THE ZOOLOGIST. 



3rd Incisors. 



Canines. 



2nd Premolars. 



Right. 



Left. 





Single rooted 



Double rooted 



Rudimentary 



Rudimentary 



2. do 



do. 



do. 



Absent 



Absent 



3. do 



do. 



do. 



Normal 



Normal 



4. Aylesbury .... 



do. 



do. 

 ( Single rooted, but \ 



Absent 



do. 



5. do 



do. 



\ showing signs of fu- I 

 1 sion of the two roots ) 



Normal 



do. 



6. Wellingborough 



do. 



do. 



do. 



do. 





do. 



do. 



do. 



do. 



8. do 



do. 



do. 



do. 



do. 



9. do 



do. 



Double rooted 



do. 



do. 



10. do 



do. 



do. 



Absent 



Absent 



11. Wellingborough 



do. 



Single rooted 



Normal 



Normal 



It will be seen from the above table that only one specimen 

 (No. 11) conforms to the type as described. I have since, by the 

 courtesy of Mr. Oldfield Thomas, been allowed to inspect a con- 

 siderable number of skulls in the collection of the British 

 Museum (Natural Histoiy). I then found that a large propor- 

 tion, probably half, of the skulls had double rooted canines, one 

 having a single root on one side and double on the other, also 

 that several show variations in the size of the second upper 

 premolar. This tooth was in some cases extremely small and 

 crowded for space, but, so far as I observed, in no case entirely 

 absent, as in my specimens, Nos. 2 and 10. 



Bearing in mind the third paragraph quoted above, I think 

 this variation of the second premolar, which can be traced 

 through all stages, from normal size to absence, is very inte- 

 resting, and probably points to E. europcsus being in a state of 

 transition to a condition similar to that mentioned as occurring 

 in E. micropus and pictus. 



From the above observations it is evident that the teeth of 

 E. europcens are extremely variable, and that the fact of the in- 

 cisors being single or double rooted will no longer hold good as 

 distinguishing this species from all others. 



It will be interesting to see whether the study of a larger 

 series of skulls will show any specimens with double rooted third 

 incisors ; if it does not do so, this may perhaps still be taken as 

 a distinguishing character, provided that the study of a large 

 series of skulls belonging to other species shows that in them the 

 third incisor is invariably double rooted. 



