THE ANCESTRY OF BIRDS. 607 



Proven9al summits some nameless calamity overtook him, from greedy- 

 kestrel or from native sportsman, and left him here, a sheer hulk, for 

 the future contemplation of a wandering and lazy field-naturalist. 

 Fit text, truly, for a sermon on the ancestry of birds ; for this solid 

 tail-bone of his tells more strangely than any other part of his whole 

 anatomy the curious story of his evolution from some primitive lizard- 

 like progenitor. Close by here, among the dry rosemary and large- 

 leaved cistus by my side, a few weathered tips of naked basking 

 limestone are peeping thirstily through the arid soil ; and on one of 

 these gray lichen-covered masses a motionless gray lizard sits sunning 

 his limbs, in hue and spots just like the lichen itself, so that none but 

 a sharp eye could detect his presence, or distinguish his little curling 

 body from the jutting angles of the rock, to which it adapts itself 

 with such marvelous accuracy. Only the restless sidelong glance from 

 the quick upturned eye suffices to tell one that this is a living animal 

 and not a piece of the lifeless stone on which it "rests like a shadow." 

 A very snake the lizard looks in outline, with only a pair of sprawling 

 fore-legs and a pair of sprawling hind-legs to distinguish him out- 

 wardly from his serpentine kin. Yet from some such lizard as this, 

 my swallow and all other birds are ultimately descended; and from 

 such a little creeping four-legged reptile science has to undertake 

 the evolutionary pedigree of the powerful eagle or the broad-winged 

 albatross. 



Reptiles are at present a small and dying race. They have seen 

 their best days. But in the great secondary age, as Tennyson graphi- 

 cally puts it, " A monstrous eft was of old the lord and master of earth." 

 At the beginning of that time the mammals had not been developed 

 at all ; and even at its close they were but a feeble folk, represented 

 only by weak creatures like the smaller pouched animals of Australia 

 and 'Tasmania. Accordingly, during the secondary period, the reptiles 

 had things everywhere pretty much their own way, ruling over the 

 earth as absolutely as man and the mammals do now. Like all domi- 

 nant types for the time being, they split up into many and various 

 forms. In the sea, they became huge paddling enaliosaurians ; on the 

 dry land, they became great erect dinosaurians ; in the air, they be- 

 came terrible flying pterodactyls. For a vast epoch they inherited 

 the earth ; and then at last they began to fail, in competition with 

 their own more developed descendants, the birds and mammals. One 

 by one they died out before the face of the younger fauna, until at 

 last only a few crocodiles and alligators, a few great snakes, and a 

 few big turtles, remain among the wee skulking lizards and geckos to 

 remind us of the enormous reptilian types that crowded the surface of 

 the liassic oceans. 



Long before the actual arrival of true birds upon the scene, bow- 

 evei', sundry branches of the reptilian class had been gradually approxi- 

 mating to and foreshadowing the future flying things. Indeed, one 



