262 THE MAMMALIA. 



the length and breadth of the teeth, the measure- 

 ments of which have to be made by the tenths 

 of millimetres, and thus we finally have an 

 animal of the dog species of the present day not 



with , but with molars, and we may there- 

 fore draw the very probable inference as to the 

 Eocene ancestors of the present Canidae. In the 

 above remarks we have principally followed an ex- 

 tremely clear account given by Huxley. 1 



If several small differences are taken into con- 

 sideration, the various species of the genus Dog 

 (Canis) may be formed into two groups, the one 

 represented by the Common Fox, the other by the 

 Brazil fox (Canis azarce). These differences relate 

 to the frontal depressions which are entirely want- 

 ing in the fox and are strongly developed in the 

 other group and to the form of the front part of 

 the brain. By the side of the fox we have Canis 

 fulvus,argentatus, littoralis,zerda, lagopus and others; 

 on the other hand the Jackals and Wolves, all varie- 

 ties of the Domestic Dog, Canis anthus, latrans, an- 

 tarcticus, magellanicus, cancrivorus, varieties of the 

 Dingo. In both groups subdivisions have again to 



1 Huxley, ' Cranial and Dental Characters of the Canidae,' 

 Proc. Zool Soc., 1880. 



