xxiv. 15 PAEDOMORPHOSIS 651 



2-5 X io 9 cortical cells, to 32 in * Pithecanthropus (4-3 X io 9 ) and 33 

 in Homo (ioxio 9 ). 



In development of powers of obtaining information with the nervous 

 system man is only showing an accentuation of the characteristics of 

 mammals in general and especially primates. With this goes the low 

 reproduction rate, slow development, and great post-natal care. The 

 retardation of development of somatic characters seems to have been 

 the basis of many human features. As Bolk pointed out man resembles 

 in many ways a foetal ape, rather than an adult one. Thus the position 

 of the head, at right angles to the vertebral column, is that found in 

 foetal apes. The late fusion of ossification centres, lack of hair, external 

 genitalia, structure of hand and foot and many other features point the 

 same way. In addition to this general retardation there have no doubt 

 been many special developments, such as formation of the nose, 

 lengthening of the pollex and elaboration of the organs of speech and 

 the muscles of expression. 



This paedomorphosis in man, producing teachable, cooperative 

 individuals may well be the factor that has made possible the develop- 

 ment of complex societies and their tools. By efficient communication 

 man is able to produce a cumulative store of information outside his 

 mortal body and passed on not only to few individuals, as is the genetic 

 store, or that passed by word of mouth, but to many. Each individual 

 thus 'inherits' not from two or few parents but from the accumulated 

 memory store of a large population. It is perhaps this 'multi-parental' 

 inheritance of information that has changed man so rapidly in the past 

 and is likely to do so even faster in the future. Success will clearly be 

 for those populations that are able so to cooperate as to discover and 

 transmit more and more information. 



