400 



GENERAL BIOLOGY 



of the femur indicates that its owner walked in an erect position and 

 was about as tall as men now are. From the parts thus found a so-called 

 "reconstruction" was made to show what the reconstructor thought the 

 individual must have looked like. The name Pithecanthropus erectus is 

 applied to the individual who once possessed these bones (Fig. 248). 

 The bones are presumably from the early Pleistocene period. 



At another time a lower jaw with its teeth was found near Heidel- 

 berg in Germany (Fig. 247, C). As the teeth are not ape-like, but ap- 

 proach those of man, the individual who possessed them has been called 

 Homo-heidelbergensis. The fossil remains of various animals found in 

 the same region with the Heidelberg jaw give us the age of this find 

 as that of the second interglacial period, which means that this jaw is 

 only about one-half the age of Pithecanthropus erectus. 



In 1856 there was found in Prussia the skeleton of what is called the 

 Neanderthal man (Fig. 247 B, and 248), or Homo-neanderthalensis 

 which comes from about the fourth glacial period, so that it is about one- 

 third the age of the Heidelberg man. 



Fig. 248. 



Restoration of prehistoric men. Left, Pithecanthropus 

 erectus; middle, Homo neanderthalensis, modeled on the 

 Chapelle-aux-Saints skull ; right, Cro-Magnon man, modeled 

 on type skull of the race. (From the original busts of, and 

 by courtesy of, Professor J. H. McGregor.) 



Then in France and Wales a number of skeletons have been discov- 

 ered in which the skull is narrow and the face broad, something like that 

 of the Esquimaux. The cheek bones and chin are also prominent. Pro- 

 fessor J. H. McGregor has molded busts in accordance with his idea of 

 what such men must have looked like (Fig. 248). 



There is no connection whatever between these various forms so we 

 cannot in any way prove they are a genetically continuous series. All 

 conclusions built upon these finds must, therefore, be purely conjectural. 



From the evidence presented here, we note the fact that many pres- 

 ent-day forms of both plants and animals are unlike their ancestors. We 

 are, therefore, confronted with four possible explanations of why they 



