the same manner and resemble the maxillae of the higher Crustacea.* (*
"The maxilla of the Decapod-larva (Krebslarve) is a sort of Phyllopodal
foot" (Claus).) We might regard the Phyllopoda as Zoeae which have not
arrived at the formation of a peculiarly endowed abdomen or thorax, and
instead of these have repeatedly reproduced the appendages which first
follow the Nauplius-limbs.

Of the Copepoda--some of which, living in a free state, people the fresh
waters, and in far more multifarious forms the sea, whilst others, as
parasites, infest animals of the most various classes and often become
wonderfully deformed--the developmental history, like their entire
natural history, was, until lately, in a very unsatisfactory state. It
is true, that we long ago knew that the Cyclopes of our fresh waters
were excluded in the Nauplius-form, and that we were acquainted with
some others of their young states; we had learnt, through Nordmann, that
the same earliest form belonged to several parasitic Crustacea, which
had previously passed, almost universally, as worms; but the connecting
intermediate forms which would have permitted us to refer the regions of
the body and the limbs of the larvae to those of the adult animal, were
wanting. 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