i:>4 TACK sK(H;siii;nr. 



Of tho vi'iv imini'nms wdiks on tlu' iiiariiu' ( ) .s t r a c o d s that Ikivc a])pcarcd siuco 

 the beginning of this periotl only a few of the most important can be iin'iitioned here: W. B.MliD, 

 1850a. J. D. Dana, 1852. W. LIUEHOHG, 1853, G. O. Saks, 1865 and 1887, (J. 8. Hkadv, 1868 b, 

 1880. F. Mt'LLliK, 1870, V. Claus, 1873, 1874b, 1876 and ISOla, F. Daiii., 1888, G. S. BliADV 

 and A. M. Nohman. 1889 and 1896, G. W. .MtiLLER, 1890, 1894, 1906a and 1), 1908, and 1912, 

 and N. HiuscilMANN. 1912. 



The works from the earlier part of this period are- for tiic most jjurt purely classiiicatory. 

 Questions of oecologv and comparative morphology seem as a rule to have been outside the 

 sphere of interest of the authors of this time, or were at least only cursorily discussed. These 

 works are certainly not noteworthy for any great acuteness and preciseness in establishing details 

 of morphology, on the contrary the species described during this time are treated so super- 

 ficiallv, the diagnoses often consist merely of generally formulated descri})tions of the shell, 

 that in most cases it is quite impossible to identify them with certainty nowadays. Our 

 knowledge of the Ostracod system was, however, rather rapidly enlarged, the main features 

 of the natural classification of tliis group were already during this period brought within the 

 limits of our knowledge. 



Among the earlier works of this epoch one may without hesitation point out that of 

 \y. LiLJEBORG, published in 1853: ,,De Crustaceis ex ordinibus tribus: 

 Cladocera, Ostracoda e t Copepoda, in Scania occurrentibus" as the foremost, 

 both as regards the excellence of the drawings and the number and exactitude of the morpho- 

 logical details given. On the other hand this work is not distinguished by any systematic 

 acuteness; a striking weakness is shown, for instance, in the complete absence of any 

 classification into families; the O s t r a c o d s are in this work divided directly into 

 genera; in the morphological interpretation of some organs of the C y p r i d i n i d. s 

 this author was also not so fortunate. In these two respects this work is far inferior to 

 J. D. Dana's work 1852. With regard, to the forms belonging to the group Cypriformes 

 W. LlL-JEBORG attained much better results; these may be said to be a very great advance; 

 imfortunately, however, they could not be used to any great extent because most of the 

 work was written in Swedish. 



G. 0. Sars' two above-mentioned works, F. MtlLLER's essay on the genus Cypridina, 

 1870, and C. Claus' different works all show a fairly big advance in the department of morpho- 

 logical study. G. W. Mt'LLER is, however, beyond all comparison the most important author 

 for the development of this study. His monumental monograph ,,D i e s t r a c o d e n 

 des Golfes von Neape 1", 1894, dealing with the marine O s t r a c o d s in an 

 exceedingly comprehensive and exhaustive way both from the systematical, phylogenetical, 

 morphological, and oecological standpoints, immediately made this group one of the best known 

 among the marine invertebrates. 



After this work of G. W. MUller the study of the marine Ostracods may be said 

 to hnve entered on a barren period. The succeeding works — even those of G. W. MUller 

 himself — are practically all mere descriptions of species. There are, however, a few exceptions, 

 for instance N. Hirsch.aiann's meritorious little work in 1012, especially valuable for the 



