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It seems to me very probable for several reasons that the penis is of the nature of a
limb, as has been assumed bv several investiga tors; I need only point out here the great
resem-blance this organ bears to a biramous limb in those forms in which it is characterized by a very
simple structure, e. g. Asterope, Philomedes, (cf., for instance, G. W. MÜLLER, 1894. pi. 5, fig. 41)
and that it is innervated in the same way as other limbs.
First antenna: — This antenna would have had eiglit joints. The only
reason for this assumption that I am able to find in G. W. MüLLER’s work is that this
number is the largest that is observed in all the known Ostracods, „wir finden
diese Zahl als höchste bei den Poducopa und Myodocopa“. It seems to be impossible to accept
this reason as in any way decisive. From the point of view of the theory of evolution one can
of course equally well imagine a cleavage of joints as a union of them. Embryology does not
support this assumption at all, nor does comparative anatomy. The only resemblance between
this limb of a C y p r i d and a C* y p r i d i n i d is really the number of joints. Both the
equipment of bristles and the musculature are so profoundly different that they do not seem
to indicate that the different joints of this antenna in one group are homologous with the
corre-sponding joints in the other.
The same uncertainty applies to the assumption that this antenna was originally a sensory
and a locomotory organ at the same time, „vielleicht glich sie am meisten der 1. Antenne
der Cypridinide n“. According to the theory of evolution there can scarcely be any
reason against an assumption that even a first antenna that was originally used exclusively
as a locomotory organ might gradually develop as a sensory organ and vice versa. It may be
pointed out that among the Halocyprids, in the majority of which the first antenna is
exclusively or almost exclusively a sensory organ, the genus Thaumatocypris, which in many
respects is to be considered as the most primitive, has a first antenna which, as far as one can
see, serves exclusively or practically exclusively as a locomotory organ. As is seen above,
G. W. MÜLLER assumes that during the course of development sometimes one and sometimes
the other of these two functions has dominated.
In my opinion it is impossible at present to give an opinion with any great degree
of certainty as to the type of this limb in the Protostracods.
Second antenna: — It seems to me probable that the protopodite of the
second antenna in Cypridi nid s, Halocyprids and Polycopids is composed
of at least two joints; traces of the original boundary between two joints have presumably
been observed by G. W. MÜLLER in the Polycopids (1894, p. 39). On the other
hånd this author’s view with regard to the protopodite in other forms seems to me far
less probable.
In an article „M itt heil ungen über Co pepo de n“, 1893. W. GlESBRECHT
wrote as follows (p. 86) with regard to the maxilliped of the Copepoda: „Daß Glieder miteinander
verschmelzen und die Gliederzahl sich auf diese Weise vermindert, läßt sich häufig nachweisen;
aber wie Glieder verschwinden können, zumal relativ so umfangreiche und muskelerfüllte und
so nützliche wie die Basalia, das hätte CLAUS doch irgendwie dem Verständnis des Lesers näher
bringen müssen“ . . . etc. However much ope nto criticism this statement may be, I should
Penis
First antenna.
Second antenna
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