284 EVOLUTION, OLD AND NEW. 



I take it that Lamarck is here attempting to express 

 what Mr. Charles Darwin has rendered much more 

 clearly in the following excellent passage : 



"It should always be borne in mind what sort of 

 intermediate forms must, on the theory [what theory?], 

 have formerly existed. I have found it difficult when 

 looking at any two species to avoid picturing to myself 

 forms directly intermediate between them. But this is 

 a wholly false view ; we should always look for forms 

 intermediate between each species and a common but 

 unknown progenitor ; and the progenitor will generally 

 have differed in some respects from all its modified 

 descendants. To give a simple illustration : the fan tail 

 and pouter pigeons are both descended from the rock 

 pigeon. If we possessed all the intermediate varieties 

 which have ever existed, we should have an extremely 

 close series, between both and the rock pigeon ; but 

 we should have no varieties directly intermediate 

 between the fantail and the pouter; none, for 

 instance, combining a tail somewhat expanded with a 

 crop somewhat enlarged, the characteristic features of 

 these two breeds. These two breeds, moreover, have 

 become so much modified that, if we had no historical 

 or indirect evidence regarding their origin, it would not 

 have been possible to have determined, from a mere 

 comparison of their structure with that of the rock 



entre elles de maniere a former une reticulation. Cette idee qui a 

 paru sublime & quelques moderates, est e'videmment une erreur, et, Bans 

 doute, elle se dissipera des qu'ou aura des connaissances plus profondea 

 et plus gendrales de 1' organisation, et surtout lorsqu'on distinguera ce 

 qui appartient a 1'influence des lieux d'habitation et des habitudes 

 contractees, de ce qui re'sulte des progres plus ou moins avance's dans 

 la composition ou le pcrfectiounenieut de rorganisution." (p. 120). 



