78 TAGE SKOGSBERG 



like to start out from it in judging G. W. MCller's view in this case. The latter writer assumes 

 that in 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 and C y t h e r i d s the distal proto- 

 podite joint has been quite lost. But where is the proof of this assumption? As far as I can see 

 there is none. G. W. MOller brings forward in this connection the fact that in the genus Cythe- 

 rella the bending into a knee takes place between the first and second protopodite joints. But 

 this does not prove this assumption. The fact that this formation of a knee in the second antenna 

 in the Ostracods has actually taken place at different places — between the protopodite on the 

 one hand and the exopodite and endopodite on the other in Cypridinids, Halocyprids 

 and Polycopids and between two protopodite joints in Cytherella — may at least be 

 explained by assuming that this limb of the Protostracods was of so primitive a 

 type that no definite formation of a knee had as yet taken place. This assumption seems to 

 be supported by the fact that this limb differs very much in its type in the different Ostracod 

 groups. The genus Cytherella is comparatively far removed- from all other Ostracods by its 

 whole organization (G. 0. Sars as we know distinguished this genus as a special groiip, parallel 

 to Myodocopa, Podocopa, etc.). The ancestors of this genus presumably branched off from all the 

 other Ostracods at a rather early period. Perhaps this differentiation even took place so 

 early that the second antenna had not yet acquired a definite knee. At any rate this possibility 

 must be regarded as being present. G. W. MUller's view finds just as little to support it in 

 embryology as in comparative morphology. I have never found any trace of the distal proto- 

 podite joint which, according to G. W. MtlLLER, has disappeared in larvae of C y p r i d s 

 or other forms in which, according to this author, it is absent in the mature specimens. 

 Nor has G. W. MtlLLER or any other investigator of this problem ever mentioned 

 such a trace. 



Moreover, according to G. W. Muller's assumption, in the forms whose distal proto- 

 podite joint has disappeared the place on the body from which this antenna issues has developed 

 into a joint-like process. Wliat has caused G. W. MOller to assume that this process, which 

 resembles a joint very much by its type, has not been a part of this antenna from the very 

 beginning? We are given no information at all as to this; I should like once more to quote from 

 the above-mentioned work of W. Giesbrecht. This author writes as follows with regard to the 

 reduction of the basal joints of the maxillipeds that is assumed by C. Claus for the Copepoda 

 (p. 86): „Wie ist dieser Verlust namentlich fiir den hinteren Maxillipeden zu begreifen, der doch 

 durch seine Lange und die hohe Zahl (7) seiner Glieder bei den meisten der hoher stehenden 

 Copepoden zeigt, daB er eher einer Vermehrung als einer Verminderung seiner Gliederzahl 

 bedurfte, als seine Function im Herbeischaffen von Nahrung zu bestehen begann?" One 

 must necessarily follow W. GlESBRECHT in trying to find out the reason for such a 

 reduction in the number of joints. Why, one asks, has this limb, which needs to 

 be relatively long in order to fulfil its supposed function as a locomotory organ, first 

 reduced its length by the total disappearance of the second protopodite joint, and then (or 

 at tlie same time?) made up for this loss in length by the development of an accessory process 

 that does not belong to the original limb. Such a question as this may perhaps seem miscientific, 

 but it seems to be forced inevitably on the reader's attention. 



