NEW MAMMALIAN TAPEWORMS. 1017 



and of same diameter as or ivider than head, thus forming a 

 radimentary pseudoscolex. The proylottlds increase very rapidly to 

 a considerable length, the posterior being longer than broad and 

 becoming detached. JSot more than ten or a dozen anterior short 

 proglottids. Genital orifices single and irregularly alternate, 

 Excretory tubes posteriorly one on each side of body, that of one side 

 being as a rule ivider than that of ojyposite side ; in anterior segments 

 two on each side. Testes very numerous, filling u,p the ivJiole space 

 left by other organs in proglottid. Vas deferens coiled. Cirrus sac very 

 large and spherical and somewhat ^yecidiar in structure, luith an 

 eversible sac reaching the exterior through a much differentiated 

 genital cloaca. Oua7'ies posterior in segment andiuith vitelline glands 

 posterior to these. Vagina straight and narrow, opening posteriorly 

 to cirrus sac • a receptaculum seminis present. Uterus at first a 

 simple sac, later a reticulum, and later still part of the uterus remains, 

 while other eggs are imbedded singly or in groups in the medullary 

 parenchyma. Eggs without ^-shaped apparatus. 



It will be, as I think, evident from the resume of the characters 

 of this species just given, that it cannot be referred with any 

 confidence to any one of the really known genera of the Tetra- 

 cotylea. The convenient table giving a key to the various genera 

 used by Ransom in his memoir enables one to refer the species 

 from Dasyums ursinths to the neighbourhood of Oochoristica, Tcenia 

 (s.s.) or Bertiella. Of the latter genus several species are known 

 from Marsupials ; but they are not known from the present 

 genus, and appear to be nearly limited to the herbivorous (at 

 any rate Diprotodont) genera, i. e. Phalanger, Phalangista, and 

 Phascolarctos * . 



These species, however, are certainly not congeneric with that 

 which I describe in the present paper. They agree with the 

 generic definition given by Ransomt, who doubtless took them, as 

 well as the species of Bertiella from Apes and Rodents and Birds, 

 into consideration when formulating his definition. The worms 

 studied by myself show the following important differences from 

 Bertiella as defined by Ransom : — The strobilisation is different, 

 the posterior strobila being much longer than broad ; the genital 

 canals pass between the dorsal and ventral excretory vessels ; 

 the testes exist throughout the segment save where space is 

 occupied by the ovaries etc. ; the uterus is of a totally difierent 

 character ; the cirrus sac is also totally different from anything 

 figured in Bertiella. I do not feel able therefore to refer this 

 species from Dasyurus ursinus to the genus Bertiella. 



I am of opinion that the present genus is nearer to the genus 

 Oochoristica. The latter genus actvially occurs in carnivorous 

 Marsupials but in Neotropical forms, in fact in Didelphys, and not, 

 however, so far as I am aware, in Australian Marsupials. The 



* See Zschokke in Semon's ' Reise,' Jena 1898, for JB. obesa and B. semoni ; and 

 the same author, '" Neue Studien an Cestoden aplacentaler Siiugethiere," Zeitschr. 

 wiss. Zool. Ixv. 1899. for B. edulis and B. sarasinorum. Also Janicki, " Die 

 Cestodeu Neu Guinea's " in Nova Guinea, Livr. v., 1906, p. 281, for B. rigida. 



■j" Loc. cit. p. 62. 



