'^ TACK SK(»c.si;l':i;(i 



iluccd Uir a siiiglo ono out of all tluvso elovon species, nanu'ly Nesidea frequens (Ci. W. MtlLLHU). 

 Is the mandible quite similar in all these species oris it subject to variation? No information 

 is given on this point. 



It is to be noted that N. HlHSCIIMANN is his very fine essay (in the Ostracod fauna ol 

 the Gulf of Finland, 1912. has given a good diagnosis of the genus Cythere. 

 The uientthcauun | ,1 iilentifving previously described marine Ostracods most investigators also 



i thf species is un- i . c • i-i. j j. • i. 



, show verv great suiierhcialitv and uncertamtv. 



The most striking instance of this is probably J. G. E('.('.i:i;. In liioi this writer pnl)lishc(l 

 a work called ,,0 s t r a c o d e n a u s M e e r e s g r u n d p r u ii r n. g e 1 o t h e t v o n 

 1874 — 76 V o n 8. M. S. G a z e 1 1 e". Out of 149 .species included in tliis work no less than 

 almost half are stated to have been previously found in Europe in a fossilized condition, in 

 post-tertiary, pliocene, miocene, oligocene, eocene and chalk. Most of these species were from 

 antarctic regions and had not been found living in our Scandinavian seas. In other words, 

 according to this author there was a great re.semblance between the present antarctic Ostracod 

 fauna and the Ostracod fauna in Europe during the tertiary and chalk periods, a state 

 of affairs, which, if it turned out to be correct, would be of the greatest interest. G. W. MOl-LER, 

 however, undertook an investigation in order to test the identifications of this autlior and 

 arrived at a really surprising result: scarcely a single one of them was correct. G. W. MOller 

 writes as follows about this 1908, p. 144: ,,Eine solche Nachpriifung ergibt, daB kaum cine Be- 

 stimmung richtig ist; ich habe zurzeit eine groBere Zahl von Bestimmungen gepriift und nicht 

 eine richtig gefunden. (Vor Jahren habe ich die samtlichen Bestimmungen gepriift, die Resultate 

 sind mir zurzeit nicht zuganglich; soweit ich mich entsinnen kann, lieB sich nur eine Bestimmung 

 mit einiger Wahrscheinlichkeit aufrecht erhalten.)" It seems to me beyond all doubt that 

 G. W. MCller's view is correct. 



Good instances of this state of affairs are also found in G. S. Brady's work on the 

 ,,C h a 1 1 e n g e r" Ostracods. PI. XXIV in this work affords, for instance, a very good 

 proof; Cythere dictyon G. S. Brady, which, according to the statements of this author, seems to 

 have a cosmopolitan distribution, is certainly not a natural unit. 



Another very striking proof of this uncertainty will be found below in the remark under 

 Asterope aberrata. 



In short everything is vague in this field of work .... 

 nav method must This state of affairs cannot continue. A firmer basis must be created for the classi- 



, c a tor e- gg^^^Q^ ^^^j g^ f^p .j^]^ ^^^ knowledge of this group of animals. The classifier must make his 

 methods of description more strict. The general descriptions of habitus which pay attention 

 to only a few organs must disappear. Greater and greater exactitude must replace dilettantism. 

 As many organs as possible must be subjected to a careful investigation and described correctly, 

 attention being paid to the variety of the details. — In an essay entitled ,,P r i n z i p i e n 

 der Systematik, etc.", 1914, L. PLATE put forward, p. 95, the following fundamental 

 principle for modem classification: ,,Jedeskonstante Merkmal kann zur 

 T r e n n u n g von U n t e r a r t e n und A r t e n v e r w a n d t w e r d e n. " The 

 characters for distinguishing the different systematic categories may be obtained equally well 



:riptions of species. 



