40 TAGE SKOGSBERG 



As an instance of an homologization of the former kind the following may be given: 

 In 1876, p. 94 C. Clai'S explained the spine-like ventral part of the chitinous support of the 

 vibratory plate, the part that, as it were, completes posteriorly the part of this limb that is 

 called ,,the comb" in this work, as ,,Kieferhaken, der eine Beziehung zur Nahrungsaufnahme 

 zu besitzen scheint". The complete incorrectness of this explanation is shown with all desirable 

 distinctness by the fact that this chitinous part is not free, but only consists of a thickened part 

 of the wall of the body, and that a similar spine- like part also completes the vibratory plate or 

 perhaps, more correctly, the chitinous support of this organ dorsally. (It may be pointed out 

 that in forms whose fifth limb seems to represent a more primitive type, e.g. in the sub-family 

 Cypridininae,- t\ie vibratory plate of this limb is often completed ventrally by a chitinous process. 

 This process is, however, probably not homologous with the chitinous part discussed above 

 in the Asterupidae.) 



Only two out of all the preceding authors have tried to homologize the part of this limb 

 that is called „the comb" in the present work. 



One of these writers, C. Claus, 1876, p. 94 and 1888, p. 152 explained this organ as an 

 endopodite; transcribed in the terminology used by me above this would correspond to about the 

 whole exopodite. C. Claus did not give any further reasons for his view; it is to be pointed 

 out that he considered the vibratory plate to be homologous to the exopodite. 



The only writer who has made a more thorough attempt to homologize this organ is 

 G. W. MOLLEr, who has dealt with this problem on two separate occasions, 1890, p. 221 and 

 1894, p. 63. 



In the first-mentioned place we read as follows: ,,Die groBte Schwierigkeit bietet beim 

 Versuch, einen Vergleich durchzufiihren, Asterope; augenscheinlich handelt es sich auch hier 

 um eine weitgehende Reduction; der eigenthiimliche Kaufortsatz von Asterope dmhe nur einem 

 der Glieder von Cypridina entsprechen. zum mindesten der weit vorragende Theil, wenn es auch 

 nicht ausgeschlossen erscheint, daB in den vorderen Theil des borstentragenden Randes die Reste 

 von anderen Gliedern mit aufgegangen sind. Ziehen wir zum Vergleich die Bildung beim Mann- 

 chen von Philomedes heran, so konnen wir, die Berechtigung eines solchen Vergieichs voraus- 

 gesetzt, kaum daran zweifeln, daB es der Fortsatz 7 ist, aus dem der eigenthiimliche Kaufortsatz 

 bei Asterope hervorgegangen. Der Fortsatz beim Mannchen von Philomedes hat die entsprechende 

 Lage, zeigt auch bereits die eigenthiimliche Richtung. Ziemlich haufig entspringt mitten auf 

 dem Fortsatz von Asterope eine einzelne, ziemlich lange Borste; an ihrer SteUe finden wir bei 

 Asterope hilgendorfii zwei langere Borsten, die auf einem kleinen, aber immerhin deutlich ab- 

 gesetzten Grundglied entspringen, welches durch einen schmalen Fortsatz mit dem gemeinsamen 

 Stamm verbunden ist. Dieser kurze Fortsatz, ebenso wie die gewohnlich allein vorhandene 

 Borste, muB seiner Lage nach dem Fortsatz 8 an der zweiten Maxille von Cypridina entsprechen" 

 (cf. G. W. MUller, 1890, pi. XXVI, fig. 4). The joint of the fifth limb that is denoted by 

 G. W. MtJLLER as no. 7 corresponds to the joint that was denoted as the fourth exopodite joint 

 in the homologization carried out by me above for the family Cypridinidae; the joint denoted 

 by G. W. MOLLER as no. 8 corresponds to the outer lobe of the third joint of the exopodite 

 according to my terminology. Thus, according to the statement just quoted from G. W. MUller, 



