READING THE RIDDLES OF THE ROCKS 113 



various living species, for as the changes undergone by 

 the embryo are in a measure an epitome of the changes 

 undergone by a species during its evolution, so the brief 

 color phases or markings of the young are considered to 

 represent the ordinary coloring of distant ancestors. 

 Young thrushes are spotted, young ostriches and grebes 

 are irregularly striped, young lions are spotted, and in 

 restoring the early horse, or Hyracothere, Professor 

 Osborn had the animal represented as faintly striped, 

 for the reason that zebras, the wild horses of to-day, 

 are striped, and because the ass, which is a primitive 

 type of horse, is striped over the shoulders, these being 

 hints that the earlier horse-like forms were also striped. 

 Thus just as the skeleton of a Dinosaur may be a 

 composite structure, made up of the bones of a dozen 

 individuals, and these in turn mosaics of many frag- 

 ments, so may the semblance of the living animal be 

 based on a fact, pieced out with a probability and com- 

 pleted by a bit of theory. 



REFERENCES 



There is a large series of restorations of extinct animals, 

 prepared by Mr. Charles R. Knight, under the direction of 

 Professor Osborn, in the Halls of Palaeontology of the American 

 Museum of Natural History, noteworthy among them being the 

 Murals in the Hall of the Age of Man depicting the mammals by 

 which primitive man was surrounded in the days when the earth 

 was young. 



Should the reader visit Princeton, he may see in the museum 

 there a number ofB. Waterhouse Hawkins's creations creations 

 is the proper word which are of interest as examples of the early 

 work in this line. 



The (i Report of the Smithsonian Institution for 1900" con- 

 tains an article on " The Restoration of Extinct Animals," pages 

 479-49$, which includes a number of plates showing the progress 

 that has been made in this direction. 



