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these features in the same degree, but I do imagine that a gradu- 

 ally increasing elongation was more or less common to all the mem- 

 bers of the pregiraffian or preelephantine species as a result of 

 their habits. 



"To take the case of the giraffe alone, for the sake of clearness 

 — it is hardly necessary to suppose occasional droughts during 

 which those members of the community with the longest necks 

 would survive, while others starved because they were not able 

 to reach such high branches as their longer-necked fellows. An 

 extra inch or so of neck could not make so much difference as this.* 



"I do not say that the giraffe or its ancestors have not had the 

 best of it when there was a struggle for existence, and that natural 

 selection has not played its part ; the fact of the giraffe's existence 

 is proof enough that it was better adapted to its environment than 

 some of its competitors ; and the longer the neck grew doubtless 

 the greater superiority the animal would possess. 



"As to the short-necked forms which would connect the present 

 giraffe with the stock from which it originally came, their dying out 

 is not difficult to explain. The law of earlier inheritance allows us 

 to imagine a small beginning becoming more accentuated in all 

 members of a species as time goes on, and as the shorter-necked 

 forms were really the parents of the longer-necked forms, the dis- 

 appearance of the former would be due, as the lawyers say of a 

 lease, to effluxion of time. 



" Arising from and coexisting with developmental variation there 

 seems to be another factor important in differentiating species, and 

 this is the time when the offspring is produced. 



"Offspring produced early and offspring produced late in the life 

 of a parent shewing considerable developmental changes between 

 early and late maturity, or between early maturity and senility, 

 would in all probability differ to a certain extent. It is, I think, 

 reasonable to suppose that if there were, say, a decline of vigor 

 after a certain period of the parent's life, the offspring produced 

 after this time would be more likely not only to be somewhat less 

 vigorous altogether, but would probably exhibit declining vigor at 

 an earlier age than those produced before any decline of vigor 

 set in. 



*"The adults would have the best of it in a drought on account of their larger size. 

 Therefore if there were a long-necked 'sport' among the young pregiraffes it would 

 have no chance against the adults unless its neck were of a preternatural length." 



