The comprehensive and careful investigations of Claus have
filled up this deficiency in our knowledge, and rendered the section of
the Copepoda one of the best known in the whole class. The following
statements are derived from the works of this able naturalist. From the
abundance of valuable materials which they contain I select only those
which are indispensable for the comprehension of the development of the
Crustacea in general, because, in what relates to the Copepoda in
particular, the facts have already been placed in the proper light by
the representation of their most recent investigator, and must appear to
any one whose eyes are open, as important evidence in favour of the
Darwinian theory.* (* I am still unacquainted with Claus' latest and
larger work, but no doubt the same may be said of it.)
(FIGURES 53 AND 54. Nauplii of Copepoda, the former magnified 90, the
latter 180 diam.)
All the larvae of the free Copepoda investigated by Claus, have, at the
earliest period, three pairs of limbs (the future antennae and
mandibles), the anterior with a single, and the two following ones with
a double series of joints, or branchiae. The unpaired eye, labrum, and
mouth, already occupy their permanent positions. The posterior portion,
which is usually short and destitute of limbs, bears two terminal setae,
between which the anus is situated.
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