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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 pregiraffan or preélephantine 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.* 
*‘T 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 coéxisting 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 
baye no chance against the adults unless its neck were of a preternatural length.” 
