Origin of Species Variorum

→ and likewise a close similarity in the embryos of widely different animals within the same class, 1859 1860

and like-wise a close similarity in the embryos of widely different animals within the same class, 1861

and like-wise a close similarity in the embryos of different animals within the same class, 1866

OMIT 1869 1872

→ might be led 1859 1860 1861 1866

are tempted 1869 1872

→ these facts as necessarily contingent in some manner 1859 1860 1861

these facts as in some manner necessarily contingent 1866

this difference as in some manner 1869

this difference as in some necessary manner contingent 1872

→ on 1859 1860 1861 1866 1872

necessarily contingent on 1869

↑ 2 blocks not present in 1859 1860 1861 1866 1869; present in 1872

In some whole groups of animals and in certain members of other groups this is the case, and the embryo does not at any period differ widely from the adult: thus Owen has remarked in regard to cuttlefish, "there is no metamorphosis; the cephalopodic character is manifested long before the parts of the embryo are completed." Land-shells and fresh-water crustaceans are born having their proper forms, whilst the marine members of the same two great classes pass through considerable and often great changes during their development.

→ the 1859 1860 1861 1866

this is the case, and the 1869

size. In the second stage, answering to the chrysalis stage of butterflies, they have six pairs of beautifully constructed natatory legs, a pair of magnificent compound eyes, and extremely complex

antennæ

antennæ;

but they have a closed and imperfect

mouth,

mouth;

and cannot feed: their function at this stage is, to search

out by

their well-developed organs of sense, and to reach by their active powers of swimming, a proper place on which to become attached and to undergo their final metamorphosis. When this is completed they are fixed for life: their legs are now converted into prehensile organs; they again obtain a well-constructed mouth; but they have no antennæ, and their two eyes are now reconverted into a minute, single,

~~and very~~

and very

simple eye-spot. In this last and complete state, cirripedes may be considered as either more highly or more lowly organised than they were in the larval condition. But in some genera the larvæ become developed

~~either~~

either

into hermaphrodites having the ordinary structure,

and

into what I have called complemental

males,

males;

males:

and in the

latter

latter,

the development has assuredly been

retrograde,

retrograde;

for the male is a mere sack, which lives for a short

time

time,

and is destitute of mouth, stomach,

and every

other

organs

organ

of importance, excepting

those for

for

reproduction.

We are so much accustomed to see

a difference

differences

in structure between the embryo and the adult, →and likewise a close similarity in the embryos of widely different animals within the same class, that we →might be led to look at →these facts as necessarily contingent in some manner →on growth. But there is no

~~obvious~~

obvious

reason why, for instance, the

wings

wing

of a bat, or the

fins

fin

of a porpoise, should not have been sketched out with all

their

the

parts in proper proportion, as soon as any