26 THE MAMMALIA. 



and the second bone of the lower arm the radius. 

 Owen accordingly makes the names of the new 

 genera remind us of the dog, wolf, tiger, &c., 

 Cynodracon, Lycosaurus, Tigrisuchus. He then 

 speaks of the importance of the discovery and says : 

 ' If the gap in the series of animals between the 

 Mesozoic and Psychozoic air-breathers had not been 

 filled up otherwise than by reptiles, the remnant of 

 that class which has survived and reached our 

 times would have testified to the total loss of such 

 gains of organisation as had enriched the ancestors 

 and predecessors of modern tortoises, lizards, and 

 crocodiles. 



* We know now that not one of these gains has 

 been lost, but has been handed on, continued and 

 advanced through a higher type of vertebrates, of 

 which type we trace the dawn back to the period 

 when reptiles were at their best grandest in bulk, 

 most numerous in individuals, most varied in spe- 

 cies, best endowed with kinds and powers of loco- 

 motion, and with the instruments for obtaining 

 and dealing with both animal and vegetable food. 



' Has the transference of structures, it may be 

 asked, from the reptilian to the mammalian type 

 been a seeming one, delusive, due to accidental 

 coincidence in animal species independently and 



