454 BE. n. W. MAEETT TIMS ON THE 



still further increased by a comparison of tlie teeth in this Dog 

 with the corresponding teeth in other members of the Canidse. 



If pm.^ and ^2i- o^ ^^® Jackal (C. aureus) be examined and 

 compared, it will be seen that, if aoy reliance is to be placed 

 upon the homologies of cusps, there is present a very marked 

 difference. 



!Firstly, there is a large well-marked cusp (fig. 4 B, jar) forming 



Kg. 4. 



pa. 



A. The biting-surface of the Fourth Premolar and First Molar Teeth of Cyon 

 rutilans, B. Similar view of the corresponding teeth of Ca7iis aureus. 



with the two external cusps (pa and me) a complete triangle 

 present on the biting-surface of the crown of ^^ This cusp is 

 the one, I presume, the Trituberculist would regard as the 

 Protocone. Situated antero-externally to this is a second cusp 

 (d), and between this and the Paracone (pa) is another small 

 cusp (e) placed on a somewhat prominent ridge passing between 

 cusp d and the Paracone. On comparing the crown of this 

 tooth with that of the upper carnassial, it would appear that the 

 two cusps (d' and e') present on the inner part of the tooth are 

 homologous with the cusps d and e of the molar tooth, and 

 that the cusp pr of the latter tooth, the all imjjortant Protocone, 

 is absent entirely from p^. 



If, again, the upper carnassial tooth of C. aureus be compared 

 with the corresponding tooth of such a form as Ci/on rutilans, or 

 even with many examples of the common Dog, it will be seen that 

 the cusp d' present in C. aureus appears to be absent in C^on 

 rutilans (fig. 4 A), and that the only trace of a cusp on the iuuer 

 side of pm-^ in the latter animal seems to be homologous with 

 the cusp e' of the Jackal. 



I would here draw attention to the great similarity between 



