studies on innrine Ostracods 5 



It soon became clear to rac, liowever, that my investigations would have to proceed on 

 other lines. There were several causes for this. The most important of these was the scarcity 

 of material. A comprehensive and thorough examination of a group needs a material rich in 

 specimens and comprising a comparatively large number of species. For several reasons the 

 greater part of my work had to be carried out at Upsala and in this town there was only the 

 not too abundant material of the Swedish museums at my disposal. Moreover, during the 

 periods I spent at the west coast of Sweden in order to study Ostracods I soon discovered 

 how sparsely these groups were represented there — both with regard to species and to indi- 

 viduals. I had the same experience as Gr. W. MULLER had previously at Naples with regard 

 to the C y p r i d i n i d s; I found that specimens of these groups were so rare „dass ich bald 

 die Lust verloren habe, besonders nach ihnen zu suchen" (G. W. MULLKR, 1894, p. 2, remark). 

 Because of the circumstances under w^iich I was working it was thus necessary for me almost 

 completely to accommodate my studies to a material which had, on the whole, been furnished 

 once for all. A fairly abundant material was at my disposal in some groups and my work has 

 expanded round these; other groups, on the contrary, could unfortunately be treated only 

 rather cursorily because of the scarcity of the material both in species and individuals. This 

 may — at least partly — explain and account for the conglomerate character of the present work. 



I myself look upon this treatise only as a preparatory work for the really exhaustive 

 monographs on the various divisions of the Ostracods and the problems connected with 

 them, which are awaited by everyone. 



Among the problems that I was faced with during my studies of the marine Ostracods The main object of 

 and that can be advantageouslv dealt with on the basis of a material like that which was at ,'* .".'"" . '* , ," 



~ " classificalton of the 



my disposal there was, in my opinion, one esjjecially that demanded a quick and thorough mnrinc Osirar.xis. 

 examination. This problem was that of classification and so I devoted most of my time and 

 labour to it. 



Other problems, such as the comparative morphology and histology of the forms, also 

 need, of course, a new and thorough examination, as there is much to correct and add here too. 

 They may, however, be said to be so well known already — especially from G. W. MOllrr's 

 large monograph, 1894, which is so rich in morphological and histological facts — that it is not 

 absolutely necessary to reconsider them immediately if we are to have a sound development 

 of our knowledge of this group of animals. 



I do not mean by this that the main features of the current classification of the marine The main features 



_ , ." ^^, rp.T^i-i^i^->_-i of the current Oalrn- 



Ostracods are mcorrect. On the contrary, as a matter of tact 1 thmk that it is only ^ ^^^ ^^^^^^^^ ^^^ „, 

 necessary to alter these very slightly. The Ostracods, like the Arthropods in general, most correct 

 are characterized by what may be called a morphology that points outward. A consequence 

 of this is that a quite modern revision of the classification of this group of animals — i. e. taking 

 carefully into consideration as many characters as possible, both internal and external — is not 

 likely to attain residts that differ so much from those gained by older investigators, whose work 

 is marked not only by too little accuracy but by the fact that attention is paid only or practi- 

 cally only to external characters, as a modern investigation of the classification of, let us say, 

 the lower groups of worms. The latter are characterized by a morphology that — if I may say 



