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Halucypridae.
Cypridàe,
Darwin-ulidae, Nesideidae
and Cytheridae.
logous to the endopodite. The exopodite is possibly quite absent. It does not seem to be
impossible, however, that the bristle or bristles found disto-laterally on the basale are to be
explained as a remains of this branch. The large lamelliform appendage, furnished with fine
hairs, that is found dorso-proximally on this limb in all the forms of this family known so
far. is probably, on the other hånd not homologous to the exopodite. It is presumably
homologous to an epipodial appendage; this idea is supported both by the position of this
appendage — distally on the part that has been explained as the coxale, i. e. at the same
place as the epipodial appendage on the maxilla in a number of forms of the sub-family
Cwpridininae — and by its appearance, which bears a rather close resemblance to the epipodial
appendage in the last-mentioned group.
The Halocyprids have a maxilla that resembles very closely, on the whole, the type
that is found in the family Cypridinidae; consequently in the present work quite, the same
homologization has been carried out in both these groups. The exopodite has, however,
quite disappeared. C. Claus points out in his work of 1891 a, p. 26 the occurrence on the
inside of the endopodite of ,,ein nach innen gerichteter borstentragender Fortsatz, dessen
Deutung Schwierigkeiten bietet“; this process was homologized with the exopodite. This
author is certainly mistaken as to this. A similar process with a single bristle is also found
in Cy p r i d i n i d s; see, for instance, fig. 13 of Philomedes (Scleroconcha) Appellöfi below. *
The epipodial appendage is always absent.**
The explanation of this limb in the Cypridàe, Darwinulidae, Nesideidae and Cytheridae
seems, on the other hånd, rather uncertain. The proximal part with its three endites
of course probably corresponds, as in the preceding groups, to the procoxale and
the coxale. But does the palp, as in Cypridinids, Halocyprids and
Poly-c o p i d s, correspond to the basale of the protopodite and the endopodite or does it represent
the basale and the exopodite or only the endopodite or the exopodite? Is the vibratory plate
to be considered as homologous to the exopodite or to an epipodial appendage? Neither the
relative position of these organs, their morphology or their embryology give any certain
information on these points. The faet that it is presumably the endopodite that has predominated
in the development of the maxilla in Cypridinids, Halocyprids and
Poly-c o p i d s clearly does not justify us in assuming without further hésitation that the same branch
has also predominated in the four families mentioned above; of this the second antenna a fiords
proof. The faet that in the Cyprids, Darwin u lids, Nesideids and Cytherids
it is, in the case of the mandible, probably an epipodial appendage that is developed as a
* The same process had been already observed previously both by C. Claus, 1874 b, and by G. O. Sars, 1887
and G. \\. Müller, 1890 a. It is true that G. O. Sars did not directly state that this appendage was homologous
with the exopodite, but nevertheless he points out (p. 75) that it „ifølge sin Beliggenhed aabenbart svarer til det nedadrettede
membranøse Vedhaeng hos Cypridiniderne og den staerkt. udviklede Vifteplade hos Podocoperne“ (Translation :
On account of its position it obviously corresponds to the downward pointing membranous appendage in the
Cypridinids and the strongly developed vibratory plate in the Podocopa“).
** G. S. Brady, in his work of 1880, pi. XL, fig. 10 reproduces a maxilla of ,,Halocypris atlantica Lubbock“
(presumably Conchoecia serrulata Claus) with a strongly developed vibratory plate, and he includes this character both
in the family and the genus diagnosis. As G. O. Sars pointed out (1887, p. 75) it is presumably the vibratory plate
on the fifth limb, which, owing lo a mistake during the dissection, happened to be attached to the maxilla,
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