Animals Before Man 



gested that in the covering of feathers, which 

 enabled them to withstand changes of tempera- 

 ture, birds found their great advantage. 



It has generally been taken for granted that 

 pterodactyls were naked, like other reptiles, al- 

 though Professor Seeley has barely hinted that 

 some sort of a covering may have been present. 

 The latest contribution to the subject is by 

 Professor Williston, who found under the thigh- 

 bone of a veiy fine specimen of Nyctodactylus 

 " very vivid markings of the integument." 

 There was "no direct evidence of either scales 

 or feathers, but the numerous, regularly placed 

 patches of darker material are such as might 

 have been produced by the skin of a bird 

 where there are many feathers." He is " con- 

 vinced that the integument was not a sim- 

 ple smooth membrane over the body, though 

 what it really was he is not prepared to 

 say." 



This brings the history of our continent 

 down to the close of the Cretaceous period, 

 which ends the Mesozoic era or, as it is some- 

 times called, the Age of Reptiles, because these 



216 



