THK MYIUAPODA IX TIIR A I'STRAI.IAX MTsKUM l;i;()I,K M AW. 109 



Tlie main dilVorencc between tlie two genera lie in the 

 i'ollowinq; pfirticalars : — 



1st. Wliereas, in A('((iifJn'i(hiK, the joints of the posterior 

 gonopods are entirely free (movable) as in TriijoiiiulKx, in 

 EiicentrolKiJii,'!, both joints are fused together into a single piece, 

 in wliicli the place formerly occupied by the once existing 

 articulation is marked by oblique folds. 



2nd. The posterior gonopods of Eiireiitrdlni] ii.-< ai'e poorly 

 cliitinized, compressed, sickle-shaped organs, not unlike the 

 similar organs of Epitrigouiultt^. On the contrary, in 

 Acanthi 111 IIS, they are stout and strongly cliitinized, spoon- 

 shaped organs, which can be compared to none of the known 

 gonopods of Spirobolids. 



Another Indian species A. viiirraiji, originally ascribed to 

 Acanthi id II. -^^^ has later on been made the type of a third genus, 

 ruIijliKiiiiIiiIitis, by Pocock.^"^ To this Pocock was led by 

 Daday's statement that, in Ai'iintJiiidiis, the pores open in the 

 metazonite ; since this statement proves to be erroneous (as 

 will by seen hereafter), the validity of Pocock's genus has to 

 be tested anew, and this will only be possible when the male 

 of A. Diurraiji is known. 



ACANTHIULUS BLAIN VILLEI, Le (InilloU, 1841. 



(Plate XV., figs. 23-28). 



Juliis JILtiiiriUei, Le Guillou, Bull. Soc. Philom. Paris, 1841, 



p. 80; Gervais in Walckenaer, Hist. Nat. Ins. Apteres, iv., 



1847. 

 Crii/oiiiidKs Bhiiiiritlei, Silvestri, Ann. Mus. Civ. Stor. Nat. 



Genova, xxxiv., 1894, p. 95. 

 SplrohoJus deiitatus, Daday, Loc. cit., 1898. 

 Acaiithiid lis ])Iaiiiri!lei, Gervais, Loc. cit., 1844; Bollman, 



Bull. U.S. Nat. Mus. No. 46, 1893; Pocock, Loc. cit., 1893 



and 1903 ; Bnilemann, Lnc. cit., 1903. 



" Pocock— Ann. Mag. Nat. Hist. (6), xi., ISB:], p. 136. 

 1^ Pocock — I8'<i'.'>, Loc, cit., p. 5ol. 



