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fully developed in this primitive form than in the sub-family Cypridininae and, as in the latter,
it was armed witli numerous bristles.
Whieli of the explanations described above, C. Claus’s, (4. \V. MüLLER’s of 1890 and
that of the same investigator of 1894 is to bo considered correct — judging from the view of
the method of homologization applied by me above to the families Polycopidae, SarsieUidne
and Cypridinidae? Or is it possible — judging from this point of view — that anv of them
on the whole is to be considered quite correct?
No very definite answer to these questions can be given — at least at present. The
strongly modified type of this limb and the complete absence of any known intermediate forms
seem — as has been shown above and as G. W. Müller has also previously pointed out — to
make it almost impossible to carry out a certain homologization of this organ at the present time.
It seems to me very improbable that, as G. W. Müller assumée! in 1894, the comb
has developed only from the part denoted above as the second joint of the exopodite, on account
of the faet that this organ issues near the base of the limb. The same reason militâtes to an
even greater extent against G. W. Müller’s assumption of 1890. It seems to me most probable
that the proximal part of the comb has been formed by what I termed above the
protopo-dite, its distal part by what is called above the first and second joints of the exopodite. The
long bristle (or the two long bristles) witli the short bristles situated near it (them) on the lateral
side of the comb presumably belong, according to my idea, to what I have called the third and
fourth exopodite joints; on the other hancl it seems quite impossible to decide whether they
belong to onlv one of or to both these joints. It is uncertain, however, whether this
homologization is more correct than that worked out by G. W. Müller. It is at present based
only on such weak arguments as the relative positions of the different parts.
The vibratory plate on this limb is of about the same type as in the families Polycopidae.
Sarsiellidae and Gypridinidae and must certainly behomologized with this organ in these families.
According to the explanation given above it is eonsequently to be considered as an epipodial
appendage. Cf. the adjoining figure IV : 3, 4.
Family Halocypridae: At the first glauce there seems to be a great gap between the type
ol the fifth limb in the families SarsieUidne and Cypridinidae and that fourni in the same organ
in the family Halocypridae. While in the two first-mentioned families this appendage is
developed as a more or less typical foliaceous limb, in Halocypridae it is a typical rod-shaped limb.
Still it is possible to show, although with a certain amount of doubt, which parts of this limb
are homologous in these three families.
If the homologization employed above is applied to the fifth limb of the H a 1 o c y p rids
we sliall find the following results: The vibratory plate is tobe considered as homologous to the
same organ in the preceding families and is eonsequently to be denoted as an epipodial
appendage. I he three distal joints are probably to be homologized witli the process that
is denoted by me above as the exopodite. The protopodite, which is proportionately
almost as large as in, for instance, the Cypridinidae, is sometimes divided into two joints,
which are often only weakly marked off from each other, a proximal one, on which the
vibratory plate issues which is to be considered as a procoxale and a coxale, and a distal
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