Full resolution (JPEG) - On this page / på denna sida - Sidor ...
<< prev. page << föreg. sida << >> nästa sida >> next page >>
Below is the raw OCR text
from the above scanned image.
Do you see an error? Proofread the page now!
Här nedan syns maskintolkade texten från faksimilbilden ovan.
Ser du något fel? Korrekturläs sidan nu!
This page has never been proofread. / Denna sida har aldrig korrekturlästs.
little verruciform appendage, unjointed and without bristles. ln my opinion this appendage
corresponds to the exopodite of this limb. In the case of this appendage in the genus
Conch-oecia this explanatà >n has already been adopted by preceding investiga tors; (G. W. MÜLLER,
1894, p. 49); in Thaumatocypris, on the eontrary, this appendage is not even mentioned in
<mr on ly description of this genus (G. W. MÜLLER, 1906 a). In most species of the genus
Conchoecia the proximo-medial one of these appendages is represented by a small, verruciform
process, which is furnished distally with a single bristle ; in other species of this genus there is
ouly a bristle developed at this place; in a few forms there is no trace at all of this appendage.
In the species of the genus Euconchoecia that 1 had an opportunity to investigate this
appendage was represented only by a bristle; no trace of any verruciform process could be observed.
In Halocypris this appendage seems always to be quite absent. Thaumatocypris, which is
in many respects the most primitive genus arnong the H a 1 o c y p r i d s, is very
iuter-esting in this respect. In this genus there is at the corresponding place on the mandible
„eine ovale Warze mit 2 Borsten an ihrem Vorderrand“ (G. W. MÜLLER, 1906 a, p. 41).
This appendage, which has not been observed by preceding investigators in the case of
the genera Conchoecia and Euconchoecia, must certainly be regarded as an epipodial appendage.
This qssumption is supportée! by its position; that it can scarcely be homologous with the
exopodite is shown, of course, by the fact that another appendage, presumably homologous
with the exopodite, is found on this joint.
With regard to this appendage in the genus Thaumatocypris G. W. MÜLLER writes as
follows, 1906 a, p. 42: „Bemerkenswert ist. der warzenartige Anhang an der medialen Seite
des 1. Tastergliedes. Einen Anhang trägt dieses Glied bei den O s t r a c o d e n ziemlich
allgemein, aber deutlich lateral (Podocopa) oder dorsal (Mehrzahl der Myodocopa). Dieser
Anhang wird als Außenast des Tasters gedeutet. Es kann kaum zweifelhaft sein, daß der hier
beschriebene Anhang dem als Exopodit bezeichneten zum mindesten der Myodocopa homolog
ist, doch widerspricht dieser Deutung die deutliche mediale Lage. Wahrscheinlich haben wir
es hier mit einem auf die mediale Seite verschobenen Außenast zu thun, wenigstens scheint
mir diese Deutung noch die einfachste und nächstliegende, sobald wir überhaupt eine
Homologie dieses Anhangs und des sogenannten Exopodits bei den anderen Ostracoden
annehmen.“
For reasons given above I cannot accept the interpretation of this appendage as
homo-logous to the exopodite in Cypridinids, H a 1 o c y p r i d s and P o 1 y c o p i d s. On the
other hånd it seems to me rather likely that it is homologous with the vibratory plate in
C y p r i d s, D a r w i n u 1 i d s, N e s i d e i d s, C y t h e r i d s and Cytherellids. The
laet that this appendage is placed laterally in the five latter groups and medially in
Thaumatocypris (and other li a 1 o c y p r i d s) cannot, as G. W. Müller lias shown in the quotation
given above, be considered any decisive argument against this homologization. (It is to be
noted that the exopodite in the H a 1 o c y p r i d s too is somewhat, though only slightly,
displaced medially). lf this line of argument is correct, the conséquence of it would be
that the vibratory plate on the mandible in C y p r i d s, D arwinulids, N e s i d e i d s,
< yt heri d s and Cytherellids is not, as has been assumed by preceding a uthors,
<< prev. page << föreg. sida << >> nästa sida >> next page >>
