EARTH DRAGONS. 



177 



from the legitimate object of this book, and 

 must accordingly be left for another volume 

 which we propose to devote to Mammal Life. 



But, as we have already hinted, besides these 

 singularly mammalian types yet other types 

 existed which, somewhat differently constituted 

 to the forms which gave birth to such dis- 

 tinguished progeny, developed and intensified 



FIG. 13. Outline restoration of the skull of an Extinct Mammal-like 

 Reptile Cynognathus. Note the general dog-like shape of the 

 skull. After Smith Woodward. 



their several peculiarities, so that they eventu- 

 ally died out unmistakable reptiles. Since they 

 too present traces of distinct mammalian lean- 

 ings, we may regard them as creatures striving 

 after an unattainable ideal, achieved, however, 

 by people of their own blood. 



The forms in question constitute three distinct 

 groups. The most primitive of these, that is to 

 say, the nearest to the ancient giant Salamanders 

 or Labyrinthodonts, the ancestral stock just re- 

 ferred to, is that represented by an anomalous 

 M 



