nr. TAGE SKOGSBERO 



the P r o t o s t r a c o d s consisted of two simple sacks situated in the posterior part of the 

 body; from each of these sacks there was a simply constructed duct, opening out ventrally 

 just in front of the fvirca; on the other hand it seems to me to be quite xincertain 

 whether the sexual ducts opened outwards with a simple or a paired orifice. In the males 

 the posterior pair of legs was used in copulation and was developed into the two penes. 

 The fate of this pair of legs in the females is imcertain; there is possibly a remains 

 of them in the genital verrucae. Among the recent Ostracods the most primitive con- 

 ditions seem to be found in a number of C y p r i d i n i d s. possibly, for instance, in Philo- 

 medes and Asierope. 



Hod-siiapni or^dii. Did the P T o t o s t r a c o d s have a rod -shaped organ? 



G. W. MtlLLRR does not make any statement on this point either. C. Claus expresses 

 himself (1876, p. 97) in such a way that one can scarcely doubt that he considered that they 

 had. I scarcely think, however, that they h a d. Among the recent Ostra- 

 cods this organ is absent not only in C v p r i d s, D a r w i n u 1 i d s, N e s i d e i d s. 

 C y t h e r i d s, but also in C y t h e r e 1 1 i d s and P o 1 y c o p i d s, which we are accustomed 

 to consider as being in many respects rather primitive and in the genus that is in several 

 respects presumably the most primitive among the H a 1 o c y ]) r i d s, namely Thaumatocypris. 

 Only in the C y p r i d i n i d s and most of the H a 1 o c y p r i d s is it developed. I myself 

 have only had an opportunity of investigating one species of Polycopidae. This was charac- 

 terized by two bristles, situated rather near each other on the front of the head, on 

 each side of the place where the rod- shaped organ is situated in the C y p r i d i n i d s. Do 

 these bristles correspond to the similarly situated bristles in other lower Crustacean groups? 

 Is this a primitive stage? It seems to me by no means impossible that this is the case. It seems 

 difficult to assume that a rod-shaped organ existed originally and was then completely reduced 

 in all these forms. The fact that this organ is absent in the most primitive genus of the 

 H a 1 o c y p r i d s even seems to indicate that the appearance of this organ in V v p r i d i n i d s 

 and H a 1 o c y p r i d s is not, as C. Claus has assumed, the result of common inheritance, but 

 that we have here once more a phenomenon due to convergence. 

 Smnmnrii <>/ iiiji This investigation has thus shown that while it is true that we can say with some 



rrihm^m oj G. II . degree of certaintv in the case of a number of characters that thev are original, our whole 



Mailer's opinion of i i n , , * • ,• r . i t-. ■, ■ . ' , t 



//„• Pn,iosirnro,is. Kuowledge of the organization of the P r o t o s t r a c o d s is very incomplete and uncertain, a 

 good deal more uncertain than one would imagine from G. W. MtiLLER's exposition. 



Thr jnmhiniruini G. W. MULLER givcs the rcsults of his investigation of the mutual relationships of 



tlie recent Ostracods in his monograph of 1894, pp. 188 — 191. 



rlit^f:ijir(lllon oj ill 

 /■fci'ril Oslroiijil 



roriliii 



din^ In i; 

 Miillrr. 



ir. The most important of these results is that the recent Ostracods are to be divided into 



two main natural groups, sharply divided from each other, Myodocopa and Podocopa. To the 

 former belong C y p r i d i n i d s, H a 1 o c y p r i d s and P o 1 y c o p i d s, to the latter 

 C y p r i d s, D a r w i n u 1 i d s. N e s i d e i d s, C y t h e r i d s and C y t h e r e 1 1 i d s. 



The view that these animals can be divided into two natural, sharply differentiated 

 — „scharf getrennte" — main divisions is, as is shown above, decidedly opposed to the views 

 (if (;. O. Sa!;s and G. T'l.Ars. As a matter of fact G. W. ^Niri.l.Ki; is almost alone in tliis view. 



