studios on inariiip Ostrarods 53 



to it; it may very well be considered as an accessory appendage. Neither the position, size nor 

 structure of this process form any decided argument in favour of its being a branch. The 

 position is explained by its function; it is an organ for breaking up food or carrying it to the 

 mouth or towards the masticatory appendages that are situated in front; the distal endite on 

 the maxilla has about the same position. The size is of very little value as an argument; in this 

 connection it w^ill be enough to point out that the endites on the maxilla are often of considerable 

 length, sometimes almost as long as the palp that has been explained as an endopodite. The 

 structure seems to be an argument against, rather than for, its having the nature of a branch; 

 it is always unjointed, in most cases not even bounded proximally; (a proximal boundary need 

 not, as a matter of fact, have much significance, as I have myself observed specimens of a species 

 belonging to the genus Macrocypris in which the middle one of the three endites of the maxilla 

 had a well-defined proximal boundary); finally it is practically always without muscles inside 

 itself — • contrary to the backward pointing branch; I only succeeded in observing these muscles 

 in the Halocyprids; cf. below, however, for the latter characters. 



This investigator does not bring forward any other reasons for his view. 



It ought to be clear from this that G. W. MOller has not proved in any decisive way 

 the assumption put forward by him as to the morphological nature of the vibratory plate on 

 the three posterior limbs. 



On the other hand we find that none of the investigators who adopt the view that the 

 vibratory plate on the posterior limbs is of the nature of an exopodite has advanced any decisive 

 proof for his view. The only one who has made a serious attempt to sujjport his assumption 

 by facts is G. Alm. This investigator has advanced a number of facts which seemed to him 

 to support the idea that the forward pointing process on the fifth limb of a number of C y p r i d s 

 and of C y t h e r e 1 1 a has the nature of a branch. We read in this writer's work of 1915, 

 pp. 9 — 10: ,,Diese Bildung entspricht doch was Form und Lage anbelangt den Kauladen am 

 Mandibel und der Maxille, zumal sie auch an der Innenseite des Beines sitzt, was nicht fiir den 

 Exopodit gelten diirfte, und weiter vermiBt man vollkommen etwaige Muskeln in derselben, 

 was alles gegen die Deutung als Exopodit sprechen muB." 



I have tried to show above that the shape and position of this process cannot be used 

 as proofs of its having the nature of a branch, but these characters arc equally incapable of 

 being used as evidence in favour of the opposite opinion. The position is distal on the protopodite, 

 i. e. where one would expect to find it if it were a branch. It is true that it is always unjointed, 

 but in connection witli this it may be pointed out tliat the same thing is always true of the 

 exopodite on the mandible, of which no investigator has yet denied that it has the nature of 

 a branch. With regard to G. ALM's argument that this process has no muscles it may be pointed 

 out, first, that these can be observed in the Halocyprids (cf. fig. 27 of Conchoecia sym- 

 metrica G. W. MULLER, in this treatise), secondly that muscles are also absent in the exopodite 

 of the mandible of Cypridinidae, etc. G. Alai assumes in the same work, p. 10, that the strong 

 development and individualization of the forward pointing process on the fifth limb of Macro- 

 cypris is connected with the fact that this limb is in this genus also used as a crawling leg and 

 a climbing organ and in consequence of this ,, nicht so weit nach vonie verschoben werden kann. 



