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S ammar y oj the
results of my studies
on the mutual
relations of my five main
groups.
differ ently in very closely-related forms. — I may state he re in passing that I have found a
hitherto undescribed genus*, quite without any furca; this genus is certainly closely related
to Macrocypris, a Cyprid genus which is considered, probably quite correctly, to be a
primitive one. This facts of course supports G. Alm’s view. — Other reasons too, obtained from the
seventh limb and the sexual organs, have beeil adduced by G. Alm against G. W. MÜLLEr’s
view (cf. G. Alm, 1915, pp. 18—21).
In G. Alm’s opinion the four families belonging to Cypri formes have „beinahe
gleichzeitig“ entered on two separate lines of development; Darwinulidae and Cypridae have
developed in one direction, Nesideidae and Cytheridae in the other. He thus denies „daß der
eine oder der andere Typus von dem zweiten abstammt“ (p. 17). He considers that it is
difficult to decide the question as to whether the N esi dei ds or the Cyprids are more
closely related to the original forms, but he adds, curiously enough, that this is „bei meiner
Auffassung nicht von größerer Bedeutung“.
This author sums up his view in the following words. „Das verschiedene Aussehen von
MÜLLEr’s und meinem Stammbaum liegt also darin, daß nach ihm die Nesideidae-Cytheridae
ziemlich hoch oben am Cypriden - Stamm ihre Abstammung hat, während nach meiner
Auffassung diese beiden Gruppen, einerseits Cypridae mit der kleinen Familie Darwinulidae,
andererseits Nesideidae-C ytheridae, ziemlich bald nach der Abgrenzung von Myodocopa, sich
voneinander getrennt und nachher vollkommen selbständig entwickelt haben.“ These forms
would consequently have branched off fairly soon after the Cytherelliformes. The genealogical
tree of the Ostracods has thus, according to this writer, the type shown in my fig. VIII.
This may, of course, appear to be rather similar to the genealogical tree drawn up by G. W.
MÜLLER 1894, p. 191; the difference is, however, perhaps better shown by a comparison between
this diagram and that of G. W. MÜLLEr’s as re-constituted by me in the present work, hg. IX.
C. Claus, in his work of 1876, p. 98, puts forward another view. According to him the
Cyprids have developed from the C y t h e r i d s. A. KAUFMANN took the same view
in his work of 1900, p. 244, „wenn wir die marinen Cytheriden . . . als direkte
Stammformen der Cypriden ansehen“. Neither of these two authors has tried to give any
detailed reasons for their views.
According to C. CLAUS (loc. cit.) the Cytherids have developed from the
Halocyprids „oder vielleicht besser von einer nahestehenden, bislang nicht näher
bekannt gewordenen ausgestorbenen Ostracodengruppe“. According to this writer the
pedigree of the recent Ostracods is thus of the following type: (fig. X). (This
writer does not say anything about the position of the Polycopids, Nesideids and
the Cytherellids.)
I t seems exceedingly difficult t o decide h o w f a r t h e „p e
digre e s“ of these three authors are to be considered correct. It
seems t o me not impossible that G. Alm’s view a’ s t o the
classi-ficatory position of the four families belonging to Cypriformes
i s nearer t o the t r u t h than G. W. MÜLLER’s. 0 n the other h a n d i t
* This form will be described in a following part of this work.
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