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.
basale as the first endopodite joint, the exopodite as an endite of the protopodite and the
epipodial appendage as the exopodite; cf. loc. cit. p. 219. In his large monograph, 1894, G. W.
MÜLLER retains this explanation on the wliole, but, curiously enough, he does not touch at all
on the question as to the morphological nature of the parts interpreted by me as the’exopodite
and the epipodial appendage.
The maxilla in the family Asteropidae has so far been explained as follows: According
to C. CLAUS, 1876, p. 93, it can easily be traced back to the natatorv limbs in
Phyllo-p o d s and Nebalia; ,,nach Art eines Schwimmfußes gebaut“, p. 94; the basale and the
endopodite are explained as the endopodite, the epipodial appendage as an exopodite; the endites
were observed and identified. G. O. Sars, 1887, p. 22 and G. W. MÜLLER, 1890, p. 220
and 1894, p. 56 adopted the same view as C. Claus.
With regard to the explanation of the proximal part of the maxilla with its endites in
Cyprids, Darwin u lids, Nesideids and Cytherids a somewhat different
opinion from that adopted above has in some cases appeared in the literature. I shall not
criticize these writers at any length, but merely quote what G. Alm says on this point (1915,
p. 7): „Die 3 hier von mir als Kauladen gedeuteten Stammfortsätze sind auch anders aufgefaßt
worden. Zenker, v. Daday, Claus und Kaufmann haben nämlich behauptet, daß diese
Fortsätze wirkliche Glieder sind, und zusammen mit dem kleinen, soeben als Endopodit
aufgefaßten Teil den eigentlichen und dann aus 5 oder 4 Gliedern bestehenden Endopodit bilden.
Als Stützpunkt für diese Auffassung gilt hauptsächlich das Vorhandensein kräftiger
Chitinbalken zwischen den Basalteilen der Kauladen, auch haben einige Forscher geglaubt, besondere
Muskeln für die verschiedenen Kauladen gefunden zu haben. Diese Muskeln dienen aber, wie JENSEN
gezeigt hat, zur Bewegung der Atemplatte. In den Ivauladen finden sich keine Muskeln, was
dagegen in den Endopoditen der Fall ist, und dies bekundet ohne weiteres die Verschiedenheit
zwischen den Endopoditen und den Kauladen. Auch sind die Chitinbalken nur im distalen Teil
des Stammes vorhanden, und sind natürlich nur als Stützorgane der Kauladen aufzufassen.“
5th. 6th and 7th F i f t h, s i X t h and seve n t h 1 i m b s: — On account of the great resemblance
between these appendages in many groups it seemed best to deal with them together.
These three limbs, like the maxilla, appear in rather different types in the different
Ostracod groups, and an attempt to interpret their different parts morphologically seems to
be even more difficult than the explanation of the maxilla. The difficulties in the solution
of this problem are clearly shown in the preceding literature; even with regard to the main
points we still find one unproved assumption opposed to another. I did not succeed either
in attaining a quite certain solution of these problems, although I studied them very
thoroughly. This uncertainty does not only apply to details; there still seem to be at least
two almost completelv different explanations possible.
I shall first try to give an account of these two explanations below; in this each limb
will be discussed independently, and >mder each limb the explanations of previous authors
will also be given. I shall then give the reasons that have caused me to choose one of these
t wo methods of explanation. I may, however, point out here in passing that the result of this
choice is only looked upon by me as provisory.
<< prev. page << föreg. sida << >> nästa sida >> next page >>
