756 Causes and Course of Organic Evolution 



for the procuring of food. Such have reduced the rearing 

 of sufficiently healthy offspring to a minimal or subminimal 

 point. Many of the Crustacea; the Arachnida as a whole; 

 groups of insects that are rich in species, such as the mantids, 

 the dragonflies, and many beetles; some gasteropodous and 

 many cephalopodous molluscs; groups of fishes like the sharks 

 and dogfishes, the garpikes, the cods, the pikes, and the anglers; 

 a few amphibians; snakes and crocodiles; groups of birds like 

 the Raptores; and amongst mammals the carnivorous mar- 

 supials, the carnivores, a few monkeys, and some uncivilized 

 races of man, are outstanding examples. 



The second and third groups, alike by their mode of feed- 

 ing and their frequent secretion of substances distasteful to 

 their competitors, constitute a large proportion of existing 

 animals, though greatly less abundant, we consider, in indi- 

 viduals than the fourth group. Their frequent semi-social 

 or social habits aid them not a little also, in spite of the animal 

 or mixed diet secured. 



The fourth group is examined in next chapter, and so need 

 not now detain us. 



To a certain degree — though not along exactly parallel 

 lines — it may be said that evolving man has presented four 

 stages which approximately correspond to the four stages 

 already presented. For the most primitive or hunting phase 

 in man's history is that when — as with many savage tribes 

 of the present day — he lived the family life or at most the 

 feebly social life, when he trusted wholly or mainly to the 

 chase of large animals, or secured these by competitive fight- 

 ing with others of his race. The second or pastoral presents 

 results not strictly comparable with the second stage in animal 

 evolution, but which approximate very closely in the effect 

 on the organism. 



The third or agricultural phase in man's evolution runs 

 closely parallel with the third in animal evolution, while the 

 commercial or manufacturing phase in man's history is closely 

 related to the fourth amongst animals. 



But throughout man's advancing history a marked difference 

 has been that he has struggled to retain a keen competitive 



