Studies on marine Ostracods 565 



of 1893 and 1894. G. H. Fovvler's studies of the larval stages of the H a 1 o c y p r i d s from 

 the Bay of Biscay (1909) are interesting, especially because of the application of BuooKS's law. 



The above work by G. H. Fow LKH is also of interest because in it the working supposition 

 was j)ut forward tliat all the species of the genus Conchoecia (and other H a 1 o c y p r i d s) 

 ,,exhil)it two stages with secondary sexual characters in the male". 



The oecology of the Halo c y p r i d s is almost completely unknown. G. W. MC'LLRli, Oecoi,.o,i. 



1894, put forward the assumption that these forms belong to the fauna of the bottom and that 

 it was only in inore or less exceptional cases that they travelled up among the plankton. But 

 even in a treatise published tlie same year 0. Cl.Al'S put forward strong arguments in favouj- 

 of these forms being iiolopluTiktoiiic orga7Usms. (J. H. K()\\l.i:i;. J909, dealt with the vertical 

 wanderings of the H a 1 o c y ]> r i d s. llic proportion hctweeu males and females and ,,the 

 Death -rat(>". 



Remarks: — Which of the classifications of the Ildlocypriformes described above is to nVi/e// «/ the iu'» 

 be preferred, the one worked out bv V. Glaus in 1890 or that of G. W. MUller, 1906 a? above-memioned 



'^ _ _ ■' rlassificalions of this 



As will be seen from what follows, I have in the present work followed the latter entirely, group is to h- 

 When I began my investigations of this group I considered — like G. W. Mfl.LEls, 1906 a — i>n-i,Tredf 



that it was not impossible that a careful investigation of all the organs would make possible 

 and even necessitate a splitting-up of the genus Conchoecia — sensu G. W. Mt'LLERl — into 

 a larger or smaller number of genera. But the results of my investigations quite refuted this 

 supposition. The organs to which G. W. MtlLLER had paid no attention in his work of 1906 a. 

 i. e. the mandible, the maxilla, the fifth, sixth and seventh limbs, the penis, the furca, the lips 

 and the internal organs are subject to exceedingly slight variation within this genus. A division 

 oiConchoecia into a number of genera, i. e. into units placed parallel systematically to ^4rc/<tconc//- 

 oecia, Halocypris and Euconclioccia. thus seems impossible to me too. On the other hand 

 we can — as G. W. Mt'LEF.R pointed out — distinguish more or less distinct and presumalih- 

 natural groups within the first-mentioned genus. A number of these groups are rather strikingly 

 chaiacterized, e. g. the Rotundata group by the position of the unsymmetrical glands, the Curta 

 group by the ramosity of one or more of the bristles on the first antenna. These groups, which 

 are easily defined and characterized, can, of course, be distinguished as special sub-genera. But 

 the method employed by G. W. Mi'i.l.ER seems to me preferable on account of its uniformity 

 and consistency. A number, or, more correctly, most of the groups established by G. W. Mt'Ll.EU 

 are very difficult to define; they are so interwoven in each other — often pres\imably by con- 

 vergence — that the natural position of a good many of their species is and will presumably 

 always be exceedinglv problematical. 



As has been pointed out above on this page G. H. FowLER, in his work on the planktonic a.n. Fmyhr's 

 s t r a c o d s of the Bay of Jiiscav (1909), put forward the interesting and, if correct, exceed- -"/'/'"■-•'"<"' "/ "'■" 



. .■ . . " iiialiire singes m llir 



ingly important working supposition that all the species ot the genus Conchoecia ..exhibit iiainnnirids. 

 two stages with secondary sexual characters in the male" (p. "iaS). i. e. these species have to 

 undergo a further moult after they have attained maturity. According to this author a number 

 of characters are altered during the last moult. On account of this two forms were in several 



