52 TAGS SKOGSBERO 



As a matter of fact — as has been already shown on p. 35 above — it must be considered 

 that the morphological value of the vibratory plate on the maxilla (in the families Cypridae, 

 Darwinulidae, Nesideidae and Cytheridae) is far from being settled with certainty. It is true 

 that in this work I have explained this organ as an epipodite, but I did so with reserve; the 

 possibility of its being of the nature of an exopodite must still be considered as being present. 

 Under these circumstances, in homologizing the vibratory plates on the three posterior limbs 

 it is not convenient to pay too much attention to the results attained so far in attempting to 

 homologize this organ on the maxilla. 



To support his view that the vibratory plate on the posterior limbs is an epipodial appen- 

 dage G. W. MtlLLER thus brings forward, in the first place, the proximal position of this organ 

 on the fifth and sixth limbs. As a matter of fact, however, the position of this organ on the 

 posterior limbs varies rather considerably. In a number of forms this plate is certainly situated 

 very proximally, as, for instance, on the fifth and sixth limbs of H a 1 o c y p r i d s, on the 

 fifth limb of Nesidea and on the fifth, sixth and seventh limbs of Cytherids (cf. the accom- 

 panying fig. V: 1 of the fifth limb of SclerocJdlus contortus [A. M. NORMAN]); in other forms, 

 however, we find it situated rather near the distal boundary of the protopodite, as, for instance, 

 on the sixth and seventh limbs in Nesidea; cf. the accompanying fig. V: 2 (Gr. W. MOller, 

 1894, pi. 15, fig. 35), on the fifth and sixth limbs of a number of Cyprids; cf. fig. IV: 7 

 above of the fifth limb of Macrocypris, and on the sixth limb of the family Cypridinidae, 

 fig. VII above. (If G. W. MtlLLER's explanation of the joints on the fifth limb of the sub- 

 family Cypridininae is correct, the vibratory plate is also attached close to the distal boundary 

 of the protopodite on this limb as well; cf. p. 46 above and G. W. MuLLER, 1894, p. 60, fig. 2.) 

 In those cases where the vibratory plate is situated jjroximally we need not, however — even 

 presupposing that it is of the nature of an exopodite — by any means resort to so radical an 

 explanation as G. W. MULler has adopted, namely that the ,,1. Stammglied vollstandig oder 

 fast vollstandig geschwunden ist" (and there is just as little need to explain the distal position 

 of this organ — presuming it is of the nature of an epipodial appendage — by assuming that 

 the distal joint of the protopodite has more or less completely disappeared). As has ah-eady been 

 pointed out above, the vibratory plate (probably always = the epipodite) on the mandible 

 is often more or less displaced; in a number of forms it is situated on the medial side of the 

 second protopodite joint, in others on the lateral side of tli is joint; in other words the position 

 of the vibratory plate is not always quite constant. If we apply this experience to 

 the posterior limbs, we need consequently only assume — if we suppose that the vibratory 

 plate on these limbs is of the nature of an exopodite — that in forms in which the vibratory 

 plate has a decidedly proximal position this organ is displaced proximally more than is usual. 

 (Whether we assume that the vibratory plate is an exopodite or an epipodial appendage, it 

 seems to be necessary for us to assume that this organ has been displaced in one direction or the 

 other in a number of forms.) 



As another argument G. W. MOLLER puts forward the occurrence of a forward pointing 

 process distally on the protopodite of the fifth limb of Cylherella and Macrocypris. The signi- 

 ficance of this process must not, however, be overestimated; no decisive value can be attached 



