68 THE ORIGIN OF MAN 



limbs of these animals were modified into wings 

 and, like the bats of today, they actually flew. 

 Their heads were relatively large but lightly 

 constructed and set at right angles with the neck 

 as in birds. The legs, like those of the bats, were 

 small and weak, and the tail was very short in 

 some species and long in others. They were car- 

 nivorous animals, feeding in the main on fishes, 

 small reptiles and Crustacea. Of birds only one 

 kind is known that appeared during this period. 

 This bird, about the size of a large pigeon, is 

 called Archoepteryx (from the Greek words 

 meaning ancient wing) , and has many points of 

 resemblance to the reptiles, and many character- 

 istics which recur only in the embryos of modern 

 birds. The Ichthyosauria (Greek for fish-lizard) 

 were a highly characteristic group, for though 

 they appeared in the Triassic and continued into 

 the Comanchian, the Jurassic and especially the 

 Lower Jurassic was the time of their principal 

 expansion. The ichthyosaurs were entirely ma- 



