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Sonie general
remarks about the
three posterior limbs.
( ’opulalory organs.
s i X t li and seventh 1 i m b s is t h a t w h ich is put f o rward above a n d
c a 11 e d t h e first m e t h o d o f explanatio n. It is perhaps best illustrated
by the fig. IV given above.
A few more words may be added here with regard to the three posterior limbs in the
families Halocyjpridae, Cypridae, Darwinulidae. Nesideidae and Cytheridae.
As is mentioned above, almost all writers assume that in the Crustacé,a the rod-shaped
limb has always or almost always arisen from the biramous type by a réduction of the exopodite;
upon this réduction the endopodite became —according to a number of writers — „was es am
Blattbein war: zur direkten Fortsetzung des Protopodites“ (W. GlESBRECHT, 1913, p. 32). II
the explanation adopted by me above is correct, the fifth, sixth and seventh limbs of the five
families mentioned above would thus form an important exception to a general rule. (It is,
however, to be noted that in the case of the limbs of Leptostraca J. THIELE, 1905, p. 449
arrived at a result similar to that obtained by me above; this investigator writes (loc. cit.):
„Die übrigen Körperanhänge: vorn die vordere Maxille, die Mandibel und die hinteren Antennen,
hinten die beiden letzten Pleopoden haben den einen ihrer beiden Äste verloren, an den vorderen
Anhängen wahrscheinlich den äußeren, an den hinteren vielleicht den inneren, etc.“). This
cannot, however, be considered surprising by those who, like myself (p. 24), take the view that
there was probable no far-reaching morphological difference originally between the different
parts of the limbs in Protostraca.
In exceptional cases the rod-shaped limb would have developed directly from the
folia-ceous type. (Even in these cases the distal part of the limb would be homologous with the
endopodte). As examples of such a development W. GlESBRECHT, 1913, mentioned, as is seenfrom
p. 24 above, the rod-shaped fifth, sixth and seventh limbs in the five Ostracod families just
mentioned. This assumption of GlESBRECHT’s must be regarded as very problematical. It is.
of course, connected with this author’s homologization of the vibratory plates on these limbs
with the exopodites. If we accept my view that this organ is of an epipodial nature, the
problem is obviouslv different; at least for the present it seems best to leave this assumption
out of considération.
Copulatory organs: —
I was doubtful as to the terms I should use for the male copulatory organs in the
Cypridinids.
We know that in this group the two vasa deferentia unite distally and open on an unpaired,
papilla-like little swelling situated medio-ventrally somewhat in front of the furca. On both
sides of this papilla there issue two more or less extensive appendages, in most cases bifurcated
distally; these are the organs of copulation. These two organs do not include any part of the
duets of the sexual organs; they are nevertheless called penes by C. Cl.AUS, G. W. MÜLLER and
others; no special reason for this terminology is given. A. Ramsch, 1906, most frequently calls them
penes, sometime genital limbs. On the otherhand A. Garrini, 1887, calls these organs „zarnpe
sessuali ; only the small papilla on which the sexual duets emerge is called penis by this writer.
If the state of a flairs had been the same in other Ostracod groups as in the
Cypridinids it would undoubtedly have been most convenient to denote the small median
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