122 GEOLOGICAL BIOLOGY. 



Edward Forbes on Origin of Species and Centres of Creation. 

 When we ask how. did species arise, we find two dom- 

 inant opinions have 'existed regarding the nature of the 

 antecedent condition immediately preceding the individual 

 organism in each case. According to the first view, im- 

 mediate physical ancestry has explained only the repetition 

 and perpetuation of its own morphological characters, and the 

 origin of any particular combination of such morphological 

 characters was not accounted for, except through the agency 

 of a primitive first cause. The sequence of organisms in 

 paleontology was clearly recognized by naturalists at the be- 

 ginning of the century, but neither ancestry nor environment 

 was deemed competent to explain anything but what were 

 called varietal modifications of species. It was this idea that 

 was in the mind of Edward Forbes* when he described a 

 natural-history province to be "an area within which there 

 is evidence of the special manifestations of the creative power; 

 that is to say, within which there have been called into being 

 the original or protoplasts of animals or plants." And again 

 he says: " The diffusion of the individuals of the characteristic 

 species of a province is found to indicate that the manifesta- 

 tion of the creative energy has not been equal in all parts of 

 the area, but that in some portion of it, and that usually more 

 or less central, the genesis of new beings has been more in- 

 tensely exerted than elsewhere." This notion led to the use 

 of the terms centres of creation and specific centres, at which 

 the species was supposed to have originated, and from which 

 it was distributed, or migrated in the course of time. 



Reality of Specific Centres Not Questioned; the Fact Variously 

 Interpreted. It is a well-known fact, and one that Forbes 

 clearly understood, that each natural-history province is such 

 a specific centre for rarely more than one species of each 

 genus of its fauna; or, in other words, each well-defined 

 species is typically developed in some such specific centre and 

 distributed within such a natural-history province. The 

 specific centre may not be geographic. Geography, in gen- 

 eral, is the most commonly observed criterion of distribution 



* Edward Forbes, " The Natural History of the European Seas," 1859. 



