o 



studies on mariiii! Ostracods 173 



In his large monograph on the Ostracods (1894) G. W. MUller makes a reservation 

 to this statement (p. 204) in the same way as he does to his statement with regard to the 

 relationship of the genus Asterope to Philomedes quoted above. He writes: ,,Aehnlich gilt 

 fiir Sarsiella."' — After having investigated a species belonging to the genus Rutiderma, this 

 author states once more, 1908, pp. 91 and 92, that Sarsiella is closely related to Philomedes. The 

 genus Rutiderma is assumed to be an intermediary form of these two genera. He writes 

 as follows: ,,Die verwandtschaftlichen Beziehungen denke ich mir so, daB Rutiderma von dei' 

 Reihe, welche von Philomedes-ahnlichen Formen zu Sarsiella fiihrte, sich abzweigte; sie als eiii 

 unverandertes Glied der Ahnenreihe von Sarsiella zu betrachten, scheint mir durch den Bau 

 der Mandibel ausgeschlossen." 



Is the genus Sarsiella to be considered as relatively, closely related to the genus Philomedes ? 

 With regard to the characters put forward by G. W. MtlLLER in 1890 to support this 

 assumption the following may be mentioned: 



Mandible: The endite on the coxale of this limb is not to be put forward 

 as evidence; the males of the genus Philomedes are not (or at least are not always) without 

 this process; besides, a process of this sort is also to be found in some species of Sarsiella, 

 cf. G. S. Brady and A. M. Norman, 1896, PI. LX, fig. lo. 



The fifth limb in Sarsiella shows no striking resemblance to the same appendage 

 in Philomedes, rather the other way about. 



With regard to the number of joints on the first antenna, the sixth limb and the 



sculpture of the shell it is certainly enough to refer to what I have said above, during the 



discussion of the relations of the genus Asterope. In other words these characters cannot 



be used as evidence for an assumption that Sarsiella shows agreement with Philomedes. 



In short, facts have not yet been brought forward to prove this assumption. We 



must answer the question in the negative. 



Whether the genus Rutiderma can be considered as a link between Sarsiella and RuUdenna a link 

 Philomedes I must leave quite open. In any case it is certain that this genus, as was pointed '"''»''^<'" Sarsiella 

 out by G. W. MtlLLER, is not an unchanged type in the genealogical table of Sarsiella. 



In my opinion the four families, Cypridinidae, Rutidermatidae, Sar- iirsuii. 



siellidae and Asteropidae, are variations of one and the same type and 

 were separated from each other presumably rather early, after- 

 wards differentiating independently. ^ In some characters a family shows a rather close 

 resemblance to one family, in others to another (partly due to convergencies?); in some characters, 

 on the other hand, it is more or less aberrant. 



