140 



SPECIES AND THEIR ORIGIN 



vidual, or from a pair of individuals, in each case precisely 

 resembling the existing descendants, which came into exist- 

 ance by a process outside the ordinary course of nature and 

 known as Creation. On this hypothesis the history of the 

 genus Zoothamnium would be represented by the diagram 

 (Fig. 29) ; each of the species being derived from a single 

 individual which came into existence independently of the 



Existing Individuals 



Z.arbuscula Z.alternans Z.dichotomum Z. simplex Z.affine Z.nutans 



Ancestral Individuals 



FIG. 29. Diagram illustrating the origin of the species of 



Zoothamnium by creation. 1 



progenitors of all the other species at some distant period of 

 the earth's history. 



Notice that on this theory the various species are no more 

 actually related to one another than is either of them to 

 Vorticella or for the matter of that to Homo. The in- 

 dividuals of any one species are truly related since they all 

 share a common descent, but there is no more relationship 

 between the individuals of any two independently created 



1 As the original drawing of the above figure could not be found just 

 as the book was ready for publication, the above was inserted to avoid 

 delay, for which the author is not responsible. W. N. P., April 4, 1891. 



