20 ARKIV FÖR ZOOLOGI. BAND 7. N:0 12. 



Furthermore, the mandibles of both have in commoPi 

 some peculiar features, viz. the long, lanceolate, sof t appendage 

 and a nearl}^ edentate chela (especially in the female), as well 

 as the absence of a typical flagellum, i. e. a tuft of hairs. 



Even the palpi, the terminal joint of which is not appen- 

 diciiliform as in Heterozercon, agree well with the type of the 

 Antennopliorince [comp. fig. 8 and Trägårdh 6 textfig. 8, 

 p. 12]. 



The male genital aperture bas the same position in Disco- 

 megistus as in those AntennopJiorince, the males of which are 

 known, viz. in the sternal shield; it is placed a little farther 

 back — between coxse III and TV — than in most of these, 

 in w^hich respect it agrees with Paramegistus, with which it al so 

 shares another characteristic, viz. the sternal shield being 

 separated from the ven trål shield. 



The female differs from all known Anteymojyhorince in 

 having the two characters combined : genital shield fused with 

 ventral shield, ventral and anal shield not fused, but it agrees 

 in these respects with the tritonympha 2 generans of Neo- 

 megistus julidicola, and the last character it shares Avith Par- 

 antennnlus, a genus the primitive character of which I have 

 endeavoured to prove in a previous paper [6, p. 27 — 32]. 



The only characteristics which seem to argue against pla- 

 cing Discomegistus in the Antennophorince are the following 

 three: the presence of telotarsus and ambulacres on the ist 

 pair of legs and the sucker plates. 



As pointed out above, the taxonomic value of the 1st 

 characteristic seems very doubtful; as to the 2nd one it is 

 obvious that the genera without ambulacres on the 1st pair 

 of legs descend from forms which had ambulacres; this charac- 

 teristic is thus a primitive one which Discomegistus shares 

 with the genus Sejodes, which I have placed at the root of 

 the family [6, p. 32]. Finally, the sucker plates are highh^ 

 specialized structures, and their presence does not allow us 

 to form any idea of any near relationsship with the Antenno- 

 phorince yet known; it seems that Discomegistus (and Disco- 

 zercon'\) belong to a group which has branched off from the 

 more primitive ancestors of the modern Antennopliorinoe and 

 which, instead of developing the ambulacres to large suckers, 

 has acquired a special organ for adhesion purposes, the 

 modified metapodial shields. 



