1904.] 



TO THE SYSTEMATIC CHARACTERS OP MAMMALS. 



143 



the Felidae and Tapii-idae. In these two groups the frontal area 

 shows the primitive direction, but at the base of the nasal bones 

 or the level of the orbits a reversed slope of hair is found, and 

 thus the nasal stream is directed towards the premaxillary 

 region, starting in Tapiridse fi'om bilateral nasal whorls and in 

 Felidse without any whorl. 



It is proposed to term these two leading types Primitive and 

 Derivative. 



Text-fig. 3. 



Types of arrangement of Hair on the Naso-frontal Region of Canidee (Primitive 

 type) and Felidse and Equidae (Derivative tj^pe). 



When the groups characterised by these two types are investi- 

 gated, it is found that those with the Primitive type are marked 

 off sharply from those with the Derivative a.rrangement by one 

 fact, viz., that the former possess pointed snouts which they 

 habitually carry high or in a direction approaching the horizontal, 

 whereas the latter have larger and longer heads and carry them 

 at an angle of somewhat less than 45° with the vertical line. 



List of Animal Forms with Primitive type of arrangement of 

 Naso-frontal Hair. 

 Marsupials. 



Genus llacropits. 



,, Didel])hys. 



,, Thylacinits 



,, Dasyurus. 



„ Phalanger. 



,, Perameles. 



,, Per ay ale. 



„ Tarsipes. 



