124 t. thomson flynn 



1. Introduction. 



It is proposed in the present communication to initiate the 

 pubUcation of a series of papers deahng with marsupial 

 embryology. The facts and interpretations embodied will be 

 based on result of an investigation into an amount of mar- 

 supial material now collected in the Biological Laboratory of 

 the University of Tasmania and fairly representative f)f the 

 Tasmanian fauna. 



It is evident that any attempt to solve the phylogenetic 

 problems presented I)y the mammalian group without having 

 at our disposal a large number of the facts relating to the 

 morphology and embryology of the IMetatheria will be 

 extremely unsatisfactory. 



Yet in the not very distant future, with the spread of settle- 

 ment and the almost incredible devastation caused among 

 these animals by fur-hunters and trappers — a depletion but 

 little compensated for by restrictive legislation — it may be 

 considered certain that the connected stages necessary for the" 

 elucidation of their intra-uterine development will be practi- 

 cally unobtainable. 



In this connexion it may be instructive to quote the words 

 of Hubrecht (1909), who says, in discussing placental arrange- 

 ments in the Marsupialia, that ' the early ontogenetic eveiits 

 and the different phases in the mutual relation of the blasto- 

 cyst and mucosa ought to be fully known in order to furnish 

 us with all the data that can be lirought to bear on this impor- 

 tant question. And it is to be fer^-ently hoped that those 

 genera that are very rapidly diminisiiing in their native land, 

 some of them even on the verge of disappearance, may yet 

 be fully investigated before they have been exterminated, 

 and have tliereb}" become as mute on this important point 

 as are their fossil predecessors.' 



Of such disappearing genera two may be mentioned, Thyla- 

 cinus and Sarcophilus, both certainly primitive in 

 the morphology of their genital organs, and for that reason 

 alone possessing important possibilities with regard to their 



