8 TAdi'; sKc)(isiii';i;(; 



duced for a single one out of all these eleven species, namely Nesidea frequens (G."W. MULLER). 

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

 is given on this point. 



It is to be noted that N. HirschmanN is his very fine essay on the Ostracod fauna of 

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

 The identification lu identifying jjreviously described marine Ostracods most investigators also 



o/ iiw^specics^is an- ^^^^^ ^^^^ ^^^^^ Superficiality and uncertainty. 



The most striking instance of this is probably J. G. Egger. In 1901 this writer published 

 a vv(jrk 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 o b e n, g e 1 o t h e t von 

 1874 — 76 von S. M. S. G a z e 1 1 e". Out of 149 species included in this work no less than 

 almost half are stated to have been pi'eviously 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 resemblance 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. MULLER, 

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

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

 writes as follows tibout this 1908, p. 144: ,,Eine solche Nachprlifung ergibt, daB kaum eine Be- 

 stimmung richtig ist; ich habe zurzeit eine groBere Zahl von Bestimmungen gepriift imd 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. \V. Muller'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. PL 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 sliort everything is vague in this field of work .... 

 .1 nc.i' iHctkud must This State of affairs cannot continue. A firmer basis must be created ion the classi- 



>,, unite lor tie e- g^atiou and so for all our knowledge of this group of animals. The classifier must make his 



scnptions of species. o o i 



methods of description more strict. Tlie general (U'scriptions of habitus wliidi pay attention 

 to only a few organs must disappear. (ii-eat(M- and greater exactitude must I'ephice 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 By stem at ik, etc.", 1914, L. Plate put fcu-ward, p. 95, the following fundamental 

 principle for modern classification: ,,,1 e d (> s k o n s t a n t e M e r k in a 1 k a n n z \i r 

 T r e II n u n g v o ii U n t e r a r t e i\ u n d A i' t e n v c i' w a n d t w o r d e n." The 

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



