CHAP. XVI Backboned Animals 259 



animals as the Surinam toad i^Pifa americana) and the Obstetric 

 frog {Alytes obsletricans) suggest that the Amphibians make ex- 

 periments in eugenics. 



"J. Reptiles. — Fishes and Amphibians are closely allied ; so 

 Reptiles are linked to Birds, and more remotely to Mammals also. 

 Those three highest classes — Reptiles, Birds, and Mammals — are 

 very different from one another, but they have certain characters in 

 common. Most of them have passed from the water to dry land ; 

 none of them ever breathe by gills ; all of them have two embryonic 

 birth-robes — amnion and allantois — which are of great importance 

 in early life. Compared with the other Vertebrates, the brains are 

 more complex, the circulation is more perfect, the whole life has a 

 higher pitch. As symbols of mammal, bird, and reptile, take the 

 characteristic coverings of the skin — hair, feathers, and scales. 

 Hair typifies strength and perhaps also gentleness ; feathers suggest 

 swift flight, the beauty which wins love, and the down which lines 

 the warm nest ; scales speak of armour and cold-blooded stealth. 



But we need not depreciate reptiles, nor deny the justice of that 

 insight which has found in them the fittest emblems of the omni- 

 potence of the earth. If Athene of the air possesses the birds, 

 surely the power of the dust is in the grovelling snakes. Few 

 colour arrangements are more beautiful than those which adorn the 

 lithe lizards. The tortoise is an example of passive energy, self- 

 contained strength, and all but impenetrable armature. The 

 crocodiles more than the others recall the strong ferocity of the 

 ancient extinct dragons. Nor should we judge reptiles exclusively 

 by their living representatives, any more than we should judge 

 the Romans by those of the decadent Empire. It is interesting to 

 remember the long-tailed toothed Archmopteryx, the predecessor of 

 modern birds, just as it is to recall the giant sloths which pre- 

 ceded the modern Edentate mammals ; but it is essential to include 

 in our appreciation of Reptiles the giant dragons of their golden 

 age. Most modern forms are pigmies beside an Ichthyosaurus 25 

 feet long, a Megalosaurus of 30, a Titanosaurus of 60, or an 

 Atlantosaurus of 100, all fairly broad in proportion. We have still 

 pythons and crocodiles and other reptiles of huge size, and we do 

 not deny Grant Allen's remark that a good blubbery " right whale " 

 could give points to any deinosaur that ever moved upon Oolitic 

 continents, but the fact remains that in far back times (Triassic, 

 Jurassic, and Cretaceous) reptiles had a golden age with a pre- 

 dominance of forms larger than any living members of the class. 

 Besides size, however, the ancient saurians had another virtue, 

 apparently possessed by both small and great — they were pro- 

 gressive. For, with toothed birds on the one hand and flying or 

 flopping reptiles on the other, it seems probable that birds had 



