1880.] 



DENTAL CHARACTERS OF THE CANID^. 



24& 



other words, in the macrodont Alopecoids these teeth are not merely 

 larger but they are more differentiated, the sectorial teeth becoming 

 increased out of proportion to the rest. 



Fig. 6. 



The crowns of the cheek-teeth of C. argentatus (A, A') and C, littoralis (B, B'). 



Those of C. argentatus are of the size of nature ; those of C Uftoralis are 



enlarged in the proportion of 4 : 3, and consequently are larger by one 



third than the natural size. This enlargement has the advantage of 



giving the same length to "^' - in both, and thus enabling the relative 

 dimensions of the teeth to be Seen. At the same time, inasmuch as the 

 length of the basicrauial axis in the skull of C. argentatus is to that in 

 C. littoralis as about 4 : 3, the figures fairly represent the actual morpho- 

 logical relations of the teeth. 

 a b, a' b', cusp-lines of the lower sectorial teeth. The third lower molar in 

 B' was absent, and is figured from another specimen; its_ crown is seen 

 somewhat obliquely. 



Similar relations are observable in the Thooid series, as the fol- 

 lowing table of proportional measurements clearly shows : — 



Table IV. — Proportional Measurements of the Teeth in Thooids. 

 A B 



