106 TAGE SKOGSBERG 



differently in very closely-related forms. — I may state here in passing that I have found a 

 hitherto undescribed genus*, quite without any furca; this genus is certainly closely related 

 to Macrocypris, a CHqjrid genus which is considered, probably quite correctly, to be a primi- 

 tive one. This facts of course supports G. Alm's view. — Other reasons too, obtained from the 

 seventh limb and the sexual organs, have been adduced by G. Alm against G. W. Muller's 

 view (cf. G. Alm, 1915, pp. 18—21). 

 I In G. Alm's opinion the four families belonging to Cypriformes have ,,beinahe gleich- 



zeitig" entered on two separate lines of development; Danvinulidae and Ct/pridae have 

 developed in one direction, Nesideidae and Cytheridae in the other. He thus denies ,,daB 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 Nesideids or the Cyprids are more 

 closely related to the original forms, but he adds, curiously enough, that this is ,,beimeiner 

 Aufltassmig nicht von groBerer Bedeutung". 



This author sums up his view in the following words. ,,Das verschiedene Aussehen von 

 Muller's und meinem Stammbaum liegt also darin, daB nach ihm die Nesideidae-Cytheridae 

 ziemlich hoch oben am C y p r i d e n - Stanim ihre Abstammung hat, wahrend nach meiner 

 Auffassung diese beiden Gruppen, einerseits Cypridae mit der kleinen Familie Darwinulidae, 

 andererseits Nesideidae-Cytheridae, ziemlich bald nach der Abgrenzung von Myodocopa, sich 

 voneinander getrennt und nachher voUkommen selbstandig entwickelt haben." These forms 

 would consequently have branched off fairly soon after the Cytherelli formes. The genealogical 

 tree of the s t r a c o d s 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. 

 MiJLLER 1894, p. 191; the difference is, however, perhaps better shown by a comparison between 

 this diagram and that of G. W. MCller's as re-constituted by me in the present work, fig. IX. 



C. Glaus, 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 C y t h e r i d e n . . . als direkte Stamm- 

 formen der C y p r i d e n ansehen". Neither of these two authors has tried to give any 

 detailed reasons for their views. 



According to C. Claus (loc. cit.) the Cy the rids have developed from the 

 Halocyprids ,,oder vielleicht besser von einer nahestehenden, bislang nicht naher 

 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 jwsition of the Poly cop ids, Nesideids and 

 the Cytherellids.) 

 Summary of the re- It seems e X c e e d i n g 1 V difficult to decide how far t h e „p e d i- 



Kiiits of my sliidirs it r j. i ^ i " i -in 



nn the mutual reia- g 1" ^ e s o t these three authors are to be considered correct. It 



iionsofmyfu'emam seems to me not impossible that G. Alm's view as to the cl a s s i- 



group!,. ficatory position of the four families belonging to Cypriformes 



is nearer to the truth than G. W. MUller's. On the other hand it 



* This form will l)e ilrsci-ilird in m lullnwiiig pai-l of lliis work. 



