studies on mariru,' Ostracx)ds 173 



In his large monograph on the s t r a c o d s (1894) 6. W. Mt)LLER 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 Astewpe to Philomedes quoted above. He writes: ,,Aehnlich gilt 

 fiir Sarsiella.^' — After having investigated a species belonging to the genus RiUiderma, 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, da6 RiUiderma von der 

 Reihe, welche von PMome^^es- ahnUchen Formen zu Sarsiella fiihrte, sich abzweigte; sie als ein 

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

 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. MOller 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) wthout 

 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. 10. 



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. W'v 



must answer the question in the negative. 



Whether the genus Rutiderma can be considered as a Unk between Sarsiella and Huuderma a imk 

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

 out by G. W. MtJLLER, IS not an unchanged type m the genealogical table ot Sarsiella. 



In my opinion the four families, Cypridinidae. Rutidermaiidue, Sar- /i.-<„i, 



siellidae a n d Asteropidae, are variations of one and the same type and 

 were separated from each o t h e ]• ji r e s u ni a b 1 y rather earl y, 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 abei'rant. 



