18 Teachings or ThomarIIcxlet 



by the relation of birds to reptiles, at present 

 so clearly distinguished from each other. So 

 far as can be judged reptile life preceded bird 

 life by a considerable geological interval, and 

 the first birds were a compromise between 

 creeping reptiles as we know them, and living 

 fowl which at present navigate the air. Pro- 

 fessor Marsh of Yale first described two birds 

 the Hesperorius and Ichthyomis, which differ 

 from all existing birds in the fact that they 

 possess teeth, thus placing them near the rep- 

 tiles. Another remarkable skeleton is that of 

 Archeopteryx, which has the foot and feathers 

 of a bird, but possesses claws resembling in 

 detail the termination of the fore limb of a 

 reptile. Moreover it has a long tail composed 

 of manv vertebrae and fringed on each side 

 with feathers. The limbs of certain reptiles 

 and birds are very much alike, some reptiles 

 being of the bipedal type. Others now extinct, 

 properly classed as reptiles (the Ptcryodac- 

 tyles), were endowed with powers of flight. 



The demonstrative evidence depends chiefly 

 for its data on the structural development of 

 the horse, and it is to America that the scien- 

 tist turns to produce his proofs. In this work 

 Professor Marsh of Yale received full credit 

 from Professor Huxley. The succession of 

 forms as now 7 arranged carries us to the bot- 

 tom of the Tertiary Strata. In receding order 

 we have: first, the true horse, equus caballusj 



