3() TAGE SKOGSBERG 



basale as the first endopodite joint, tlie exopodite as an endite of tho protopodite and the 

 epipodial appendage as the exopodite; cf. loc. cit. p. 219. In his large monograph, 1894, G. W. 

 MtlLLER retains this explanation on the whole, but, curiously enough, he does not touch at all 

 on the question as to the morphological nature of the parts interpreted by me as the" exopodite 

 and the epipodial appendage. 



The maxilla in the family Asteropidae has so far been explained as follows: According 

 to C. Claus, 1876, p. 93, it can easily be traced back to the natatory limbs in P h y 1 1 o- 

 p o d s and Nehalia; ,,nach Art eines SchwimmfuBes gebaut", p. 94; the basale and the endo- 

 podite are explained as the endopodite, the epipodial appendage as an exopodite; the endites 

 were observed and identified. G. 0. Sars, 1887, p. 22 and G. W. MtlLLER, 1890, p. 220 

 and 1894, p. 56 adopted the same view as C. Claus. 



With regard to the explanation of the proximal part of the maxilla with its endites in 

 Cyprids, Darwinulids, Nesideids and Cytherids a somewhat different 

 opinion from that adopted above has in some cases appeared in the literature. I shall not 

 criticize these writers at any length, but merely quote what G. Alm says on this point (1915, 

 p. 7): ,,Die 3 hier von mir als Kauladen gedeuteten Stammfortsatze sind auch anders aufgefaBt 

 worden. Zenker, v. Daday, Claus und Kaufmann haben namlich behauptet, daB diese 

 Fortsatze wirkliche Glieder sind, und zusammen mit dem kleinen, soeben als Endopodit auf- 

 gefaBten Teil den eigentlichen und dann aus 5 oder 4 Gliedern bestehenden Endopodit bilden. 

 Als Stiitzpunkt fiir diese Aulfassung gilt hauptsachlich das Vorhandensein kraftiger Chitin- 

 balken zwischen den Basalteilen der Kauladen, auch haben einige Forscher geglaubt, besondere 

 Muskeln fiir die verschiedenen Kauladen gefunden zu haben. Diese Muskeln dienen aber, wie JENSEN 

 gezeigt hat, zur Bewegung der At(>mplatte. In den Kauladen linden sich keine Muskeln, was da- 

 gegen in den Endopoditen der Fall ist, und dies bekundet ohne weiteres die Verschiedenheit 

 zwischen den Endopoditen und den Kauladen. Auch sind die Chitinbalken nur im distalen Teil 

 des Stammes vorhanden, und sind natiirlicli nur als Stiitzorgane der Kauladen aufzufassen." 

 5ih, 6i!i and 7th Fifth, s i X t h and s e V e n t li limbs: — On account of the great resemblance 



between these appendages in many groups it seemed best to deal with them together. 



These three limbs, like the maxilla, appear in rather different types in the different 

 Ostracod groups, and an attempt to interpret their different parts morphologically seems to 

 be even more difficult than the explanation of the maxilla. The difficulties in the solution 

 of this problem are clearly sliown in the preceding literature; even with regard to the main 

 points we still find one unproved assumption opposed to another. I did not succeed either 

 in attaining a quite certain solution of these problems, although I studied them very 

 thorouglily. This uncertainty does not only apply to details; there still seem to be at least 

 two almost completely different explanations possible. 



I shall first try to give an account of these two explanations below; in this each limb 

 will be discussed independently, and under each limb the explanations of previous authors 

 will also be given. I shall then give the reasons that have caused me to choose one of these 

 two methods of explanation. I may, however, point out liere in passing that the result of this 

 choice is only looked upon by me as provisory. 



limbs. 



