studies oil mai'ine Oslracods 59 



genital papilla as a penis, as A. GarbINI has done; the copula tory organs might have conveniently 

 been called „genital limbs" or something similar. We know, however, that this is not the case. 

 On the contrary, in other groups* the distal parts of the ducts of the sexual organs do not emerge 

 between the copulatory appendages, but more or less distally on them; in other words the 

 latter are to be taken as real penes. 



The question now arises: are the copulatory organs in the C y p r i d i n i d s homologous 

 to the same organs in other s t r a c o d s. It Ls exceedingly difficult to answer this question; 

 a multitude of facts fi'om comparative morphology and embryology, which unfortunately I 

 cannot yet give, are necessary for this answer. G. W. MULler does not attempt to give any 

 definite answer to this question. He writes, 1894, p. 77: „. . . . So beschranke ich mich hier 

 darauf, die verschiedenen Moglichkeiten der Homologisirung des Penis, die ich kenne, aufzu- 

 zahlen, ohne damit behaupten zu wollen, daB damit alle Moglichkeiten erschopft sind. — 



1) Der Penis der C y p r i d i n i d e n ist das umgewandelte 8. GliedmaaBenpaar und dem 

 burstenformigen Organ der Podocopa, nicht aber dem Penis der iibrigen Ostracoden 

 (einschlieBlich der Podocopa) homolog. Der Penis der letzteren ist nicht aus einem GliedmaaBen- 

 paar hervorgegangen. Hierflir lieBc sich das verschiedene Verhalten des Penis bei den 

 Cypridiniden und den iibrigen Ostracoden anfiihren. Bei den Cypridiniden 

 nimmt er keinen Theil des Vas deferens auf, sondem steht nur neben der Miindung. Bei den 

 iibrigen Ostracoden umfaBt er den Endtheil des Vas deferens, ist selbst Begattungsrohr. 



2) Der Penis der Cypridiniden ist aus einem GliedmaaBenpaare hervorgegangen, das sich 

 bei den Podocopa gespalten und den Penis nebst dem burstenformigen Organ geliefert hat, 

 wtihrend bei den Halocypriden und Polycopiden nur die eine Halfte erhalten ist. 



3) Der Penis der Cypridiniden ist aus 2 GliedmaaBenpaaren hervorgegangen, von denen 

 das eine den Penis der Halocypriden, Polycopiden und Podocopa, das andere das 

 biirstenformige Organ der Podocopa geliefert hat. — Ich finde keine Griinde, welche die eine 

 Annahme wahrscheinlicher machen, als die andere." As for several reasons I am fully convinced 

 that the copulative organs are homologous formations in the whole Ostracod group — I regard the 

 conditions in the C y p r i d i n i d s as primitive — ■ it seemed to me best to use the term penes 

 for these organs, thereby following the terminology accepted by most previous investigators. 



It will be necessary in the future to define and amplify the special terminology for this 

 organ very considerably. The reason why this is not done here is that in the present work this 

 organ is dealt with very superficially. The complicated structure of this organ needs a very 

 thorough and comprehensive examination, a piece of w(jrk that probably needs a special treatise. 



Gills: — 



I shall only mention hi passing A. Dohrn's hypothesis (Geschichte des Krebs- 

 sta mmes) that the gills in the genus .4s<erope are homologous with epipcjdial appendages of limbs, 

 the other parts of which have now entirely disappeared. No proof of this assumption can be 

 given, but it also seems, at least at present, impossible entirely to disprove it. It may, however, 

 be pointed out that it seems much more probable that we are only concerned with accessory folds 

 of the skin without any connection originally with limbs; (on the other hand it is quite uncertain 



* The slate of afi'uirs in Polycopidac is unfortuimtely not icnowii with •t:ijiiiy. 



