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Relationship
beiween Cypridina
and Asterope.
Relationslup beiween
Sarsiella and
Philo-medes.
Cypridinid genus Crossophorus, pointed out above as primitive), the slight differentiation and
size of the penis and its shape like that of a biramous limb (what is the state of affairs in
Crossophorus with regard to this is not known).
From what has been stated above it may be clear that there are not adéquate reason to
justify an assumption that Philomedinae is inore closely related to the Asteropidae than are
other forms belonging to the sub-order Cypridiniformes. On the other hand, it is, of course,
by no means impossible that it is so. It does not seem to me impossible that those of
G. W. MÜLLER’s characters which were placed in the third category above and at least a few
of the characters put forward by me above really indicate a doser relationship between the
two first-mentioned groups. The fact that there is a possibility that these characters are more
or less primitive causes us, however, to use them only with the greatest caution as evidence
in this matter.
The absurdity of G. W. MÜLLER’s assumption that the family Asteropidae has arisen
from Philomedes-like forms in which the réduction of the maxilla and fifth limb appeared
in both males and females ought in point of fact to be so obvious to every one who knows
these forms intimately that a réfutation in addition to that which has been given above seems
scarcely to be necessary.
On the other hånd, according to G. W. Müller, loc. cit. p. 224, there were characters
to be observed that seem to indicate a doser relation between Cypridina and Asterope;
these characters were:
The first antenna: In Philomedes this has six joints, in Asterope and Cypridina
seven; Asterope is, however, strongly differentiated from Cypridina by the type of the
joints „während in Bezug auf Schlankheit wieder Philomedes in der Mitte steht“.
Gills, which are characteristic of Asterope, occur, although rarely, in Cypridina
but, on the other hand, are never found in Philomedes; this last-mentioned fact loses —
according to this author — in importance, however, if we assume that gills were
characteristic of the ancestral forms of the sub-ordo Cypridinif ormes.
It must be clear to every one who has closely studied the last-mentioned group that the
number of joints on the first antenna cannot be used to support an assumption that the
Asteropids approach the sub-family Cypridininae. The number of joints is, in reality,
not infrequently different in males and females of the same species of these groups. The
importance of the gills for the solution of this question may be said to be very small; these simple
organs may very well have developed by convergence in Cypridininae and Asteropidae.
According to G. W. MÜLLER’s statement, 1890, the genus Sarsiella also resembles
Philomedes. The characters brought forward to support this assumption are as follows (p. 226) :
„In einigen Punkten erinnert sie an die Männchen von Philomedes, so
im Fehlen des Kaufortsatzes der Mandibel und
im Bau der zweiten Maxille.
Beachtenswerth erscheint die Réduction der Glieder der ersten Antenne,
das Fehlen jeder Gliederung am Maxillarfuß,
das Auftreten von erhabenen Leisten auf der Oberfläche der Schale.“
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