t! TAOR RKOr.SRKRr. 



so — points uww inwardly, tlu'ir outer cliaractcrs incsciil only a lew (('rtaiii and |)liylotirncl :(all\- 

 inij)ortant fixed points, \vliil(\ on tlic otlicr liand. a carclul invcstigiition of the inner stiueluro 

 in those groups is often likely to give good and ini|>ortant results. 



f spreial classi- ^^^lat I refer to is the special classification 



irtiiion o/ this Even at a rather early date H AHCKI:!. put forward the su])position that the marine 



saiif/ariory. Ostracods might prove to be exceedingly rich in species. This supposition has been fully 

 confirmed by the following investigations. Thus (4. \V. MnLlJOH in his synoptic work on the 

 Ostracods in ,,Das Tierreich", 1912, includes no less than ITIli living Ostracod species 

 and of these the marine forms compose the vast majority. To jiuige from the most recently 

 published works and from the experience I had myself in working out this treatise, the number 

 is. in addition, far from exhausted. 



Under the.se circumstances it would be a great pity if the quality of the descriptions of 

 the species were not to correspond to their quantity. 



Vneertainiy Even in Fh. Dahl's work on the Cy t h e i- i d s of the Baltic, 1888, we find on p. 1 the 



i ineompteifness following Statements, mifortunately only too true, which throw light on this state of affairs: 

 ofspeeifs. >'^^^^ muBte aber bald einsehen, daB sich schon dem Vorstudium zu einer solchen Arbeit, 

 d. h. der Bestimmung der Arten, ganz erhebliche Schwierigkeiten entgegenstellten. Selbst 

 nach eingehender Priifung konnte ich nicht mit Sicherheit angeben, ob meine Bestimmung 

 wirklich richtig sei. Es lag dies theils daran, daC in der vorhandenen Literatur gar keine oder 

 ungeniigende Zeichnungen vorliegen, \ind doch diirften gerade in dieser Thiergruppe genaue 

 Zeichnungen unbedingt nothwendig sein . . . ." 



G. \V. MCller states that, out of the 1719 Ostracod species included in his work 

 of 1912, only 921 are to be considered as ,,sichere", the remaining 798 are ,,unsichere Species". 

 My own experience goes to .show that even a rather considerably greater percentage of these 

 species are to be denoted as uncertain. 



On a closer study of the numerous diagnoses of marine species of this group that are 

 found in the literature one cannot but be struck almost continually by two facts: first the 

 indefinite and uncertain nature of all that is written and secondly the fewness of the characters 

 that are taken into consideration. 



Most of these species are, as a matter of fact, so superficially described and reproduced 

 — the diagnosis consists only of a general description of the habitus — that certain identification 

 is quite impossible merely because of this. 



This superficiality has had the result that obvious errors have very often crept in. 

 Only a few authors, such as G. W. MtlLLER and N. Hirschmann, seem to have troubled about 

 any great exactitude with regard to details. But not even they can escape criticism for lack 

 of care, a fact that I had an opportunity to observe, for instance, in the case of G. W. Mulleh, 

 in a mmiber of verificatory investigations. As the conditions now are, it is at least equally 

 probable, in the cases where a diSerence is foimd between the form investigated and 

 the description or figure of a species formerly treated in the literature, that this devi- 

 ation is due to lack of precision in the description or the figure as that the difference 

 actually exists. 



