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over if the organ has been developed without Natural
Selection, and then taken advantage of by the modified
descendants, animal intelligence intervenes and not Natural
Selection. Such an explanation can only have one mean
ing. It refers to cases in which the nascent organ can be
developed without Natural Selection. But if this is so, why
do the advocates of Natural Selection maintain that the
improvements in the nascent organ must be of the highest
use to their happy possessors ? The only way of har
monising the two statements is to suppose that it is their
intention to affirm that nascent organs are generally de
veloped by Natural Selection, and that on some rare
occasions they are developed without its aid. If this is
what we are to understand, we may remark that some
writers do not by any means regard this evolution of
nascent organs without Natural Selection as an exceptional
phenomenon in nature.
Mr. Joseph John Murphy, in a letter to Nattire, says :—
“ If all perfectionment is due to the two causes of exercise through
habit and Natural Selection among variations, it is obvious that no
improvement can be effected which is not immediately useful. I be
lieve that the animal kingdom, and in all probability the vegetable
kingdom also, are full of organs which cannot have been evolved by
anything like a Darwinian process, because their immature states
cannot have been in functional activity. . . . Muller, in his
Facts for Darwin, says of the transition from the Zoea to Mysis form,
in the metamorphoses of a species of Peneus or prawn, that ‘ the long
abdomen, which just before was laboriously dragged along as a
useless burden, now, with its powerful muscles, jerks the animal
through the water in a series of lively jumps.’ The Nauplius, which
is the form in which this Peneus leaves the egg, has no abdomen ;
this is acquired when the Nauplius develops into a Zoea, and con
sists of segments which appear between the body and the tail of the
Nauplius. Muller’s account seems to show that this abdomen is
developed before it is useful to the animal, and for the purpose of
becoming useful further on in its development. . . . Another
instance of the same kind is that of those Ascidian larvae, which are
the probable origin of the vertebrata. Of what use can the dorsal
groove and the notochord be to those minute and lowly organised