II] MODE OF LIFE 43 



segments x and xi, and in some species two pairs of 

 ovaries in the two following segments. The small 

 family is very widely distributed in more temperate 

 regions, principally of the antarctic hemisphere. It 

 occurs for instance in New Zealand, South Australia, 

 the Cape, and in the northern hemisphere in Europe, 

 Western Asia, and North America. 



CHAPTER II 



MODE OF LIFE 



We have now completed a brief survey of the 

 general characters of the gi'oup of the Oligochaeta 

 which will at least serve to impress upon the reader 

 the fact that these animals are somewhat diverse in 

 structure, and that even as regards outward appear- 

 ance it is not difficult to distinguish a large number 

 of different types. These facts become all the more 

 remarkable when we reflect upon the very similar 

 conditions which surround all the species of earth- 

 worms. It is not clear how far the influence of the 

 soil differs in a tropical forest in South America and 

 in Central Africa. With divergent external conditions 

 anatomical differentiation becomes more accountable. 

 But in this case we have a lavish anatomical variation 

 which would appear to have no connection with any 



