88 TAGR SKOGSBEIIG 



(cf. G. W. MtiLLBR, 1894, p. 16), while in the higher forms it is exchisively a cleaning organ. 

 In the C y P r i d i n i d s this appendage is developed into a complicated cleaning organ; in 

 the H a 1 o c y p r i d s it certainly functions as a cleaning organ, but still it is considerably 

 less suited to this function than in the C y p r i d i n i d s. ,,Stehen nun, wie MtJLLER meint, 

 die C y p r i d i n i d e n entwickelungsgeschichtlich auf einer hoheren Stufe als die H a 1 o- 

 c y pride n, so wUrde dies in Bezug auf den PutzfuB bedeuten, daB dieser bei den hoheren 

 Formen mehr veriindert und seiner Funktion besser angepaBt ist als bei den niederen." In 

 other words in several groups this limb is not developed as a cleaning organ, in others it is most 

 complete as a cleaning organ in the most metamorphosed forms. In both high and low 

 C y p r i d s, in N e s i d e i d s, C y t h e rids and H a 1 o c y p r i d s* it begins embryologi- 

 cally as a downward and backward pointing process; only in the Cypridinids does it 

 point upwards from the beginning. In the C y p r i d s it is developed pretty far without its 

 position being altered; only at a rather late stage is it bent upwards. On the other hand 

 G. W. MULLER gives no reason for his view; nor does it seem to me possible at present to find 

 any. We seem to be compelled for the present to adopt the view assumed by G. Alm, but 

 is does not seem to me impossible that G. W. MtJLLER may be right. 



The question of why the cleaning limb has been reduced in the H a 1 o c y p r i d s is 

 one that can scarcely be answered yet. At any rate G. W. MULLER 's assumption that the 

 reduction was connected with ,,des Aufgebens der Brutpflege" seems to me, however, 

 impossible**, as this organ almost always or at least in most cases is as well developed among 



* It is to be noted that this limb in the Halocyprids is often still kept pointing backwards and 

 downwards even in the mature stage, with only its small end joint pointing upwards. It is often found in this position even 

 in dead specimens. Sometimes its end joint also points downwards. 

 The function nf the ** In this connection I should like to say a few words with regard to the function of this limb in Cypridinids, 



seventh limb. Halo r y p r i d s and C y \i r i d s. H. E. Straus, the first author to investigate this appendage in the C y p r i d s, 



assumed (1821. p. 47) that it was used ..a .soutcnir les ovaires"'. H. Milne Edwards, one of the first authors to 

 discuss the C y p r i d i n i d s, assumed (1840), presumably influenced by H, E. Straus, that this pair of limbs functions 

 as eggbearers; he calls them ,,pattes oviferes". Several succeeding authors, e. g, W. Baird, J. D. Dana, E. Grube 

 and even C. Claus in his earlier works, accepted this assumption. W. Zenker, in his work ..M o n o g r a p h i e der 

 Ostracoden, 1854", pointed out, p. 17, that H. E. Straus's assumption could not be correct. ,,Die Eier aber brauchen 

 keine Unterstiitzung, da sie von der Wandung des Eileiters und auBerdem noch von der Chitinhaut bedeckt sind." This 

 author assumed that this appendage served as a cleaning organ for ,,dic groBe Kiemenplatte mit ihren gefiederten Haaren", 

 F, MiJLLER, in his work of 1870, expressed the view that this limb functions as a cleaning organ in the Cypridi- 

 nids as well. He writes on p. 257 as follows: ,,Beobachtet man eine lebende Cypridina nitidula Oder eine C. Agas- 

 sizii mit nicht zu undurchsichtiger Schale, so sieht man die geringelten Anhange, die mit ihrem meist rechtwinklig 

 abstehenden Borstenbcsatz fast wie die Biirsten aussehen, deren man sich zum Reinigen von Glascylindern bedient, in fast 

 ununterbrochener, lebhafter Bewegung. Einem Ringelwurm vergleichbar, der aus seiner Rohre weit vorgestreckt nach 

 alien Seiten umhertastet, kriechen sie und biegen sie sich nach alien Rich tungen; namentlich an den Kiemen und in deren 

 Umgebung fegen sie und putzen sie fleiBig hin und her. Mit den Eiern, die allerdings wenigstens bei C. Agassizu innerhalb 

 der Schale der Mutter sich entwickeln, haben sie nichts zu schaffen, Sie sind bei beiden Geschlechtern in vollig gleicher 

 Weise ausgebildet." The same observations were afterwards made by other investigators, e. g. G. W. Muller, 

 1894, p, 72, for the Cypridinids, and I too have had occasion to verify them. As a further proof that we are here 

 concerned with a cleaning organ G. \V. Muller (1. c.) states that in the gemis Sarsiella he often found „den 1. FuC 

 des cJ arg verschmutzt, ja, einmal war es auch die .\lhemplatte drr Maxille und die hintere Korperhalfte"; we know 

 that in the males of this genus the 7th lind> is Cfuite absent. In Cyprids too it has been observed that this 

 appendage is, as it were, continually combing and cleaning. With regard to the Halocyprids G, \\. Muller 

 pointed out, 1804, p. 73, that this limb carries out movements that closely resemble the cleaning movements of the 

 corresponding appendage in the C y j) r i d i n i d s and he assiuiics that these niovenicnls have the same purjiose here 



