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Relationship of t ht
families.
Rh i lo medes a. von
nertm g link het iver t
(’i/prid ma and
A sterope?
Family
1. Cypridinidae
f sub-family Cypridininae
I „ Philomedinae
LI. Rutidermatidae
III. Sarsiellidae
IV. Asteropidae.
It is probable, however, that there is not complete équivalence between these four
families; yet this seems to me to be the division that best reprocliices their mutual
relations. In this case it might be said as G. W. MÜLLER wrote about the systematic position of
the genus Rutid,erma: „Aber schließlich ist das etwas Geschmackssache . . .
Here it may be pointed out that all the above-mentioned groups, Cypridininae,
Philomedinae, Rutidermatidae, Sarsiellidae and Asteropidae are certainly to be considered
quite natural.
Which is the mutual relation of the above-mentioned four families?
It still seems to he too early to try to enter more closely into this problem. For the
present I shall therefore confine myself to merely a passing reference to it.
The onlv writer so far who has dealt with the mutual relationship of the forms belonging
to these families is G. \V. MÜLLER. In his vvork of 1890 this author suggested on p. 224 that
the genus Philomedes would form a connecting link between the genus Cypridina s. 1.
and the genus Asterope. The reasons that seemed to this author to support this assumption
were as follows:
The shell: In the genera Philomedes and Asterope there sometimes appears
a sculpture of the shell in the form of prominent ridges „die wir nach ihrem gesammten
Verlauf als homolog bezeichnen müssen“; such ridges are, on the other hand, not
found in Cypridina. The selvage is smooth-edged in Cypridina, in Philomedes it is
broken up into hairs at the margin, in Asterope it is quite broken up into hairs.
Mandible: The endite on the coxale is small and simple in Cypridina, somewhat
larger and bifurcated in Philomedes, large and very deeply bifurcated in Asterope. The
endite on the basale is large in Asterope, somewhat weaker in Philomedes, almost
com-pletely or quite completely absent in Cypridina.
With regard to the maxilla and the fifth limb the males of Philomedes would
form a kind of transitional type between Cypridina and Asterope.
The sixth limb is jointed in Cypridina and in this genus the different joints are
moved by special muscles, in Philomedes this appendage is jointed, the different joints
would, however, not be moved by special muscles, in Asterope it is quite unjointed.
Seventh limb: In the genus Cypridina „sind beide Schenkel der Zange sehr ungleich,
bei Philomedes sind die Unterschiede geringer, bei Asterope sind sie fast ganz geschwunden“.
The rod-shaped organ, like the upper lip, would be alike in Philomedes and Asterope;
the upper lip in these two genera would be specially characterized by the absence of
glandulär fields.
On the furca there sometimes appear secondary claws, „Nebendornen“
medes and Asterope-, in the genus Cypridina there would be no such claws.
in Philo-
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