•278 PROCEEDINGS OF SECTION D. 



In view of the probable land connexion between Australia and 

 South America through the Antarctic, a connexion which is supported 

 by a good deal of biological evidence, it is unfortunate that practically 

 nothing seems to be known about the frog trematodes of South 

 America. A pretty close similarity has, however, been shown by 

 Zschokke to exist between some cestode parasites of South America 

 and Australian marsupials. Much the same condition of afiairsas 

 has been described for frogs can be shown to exist between the trematode 

 parasites of birds living in particular zoo-geographical regions, as well 

 as those of reptiles and of mammals. 



To mentions only a few from birds — the various species of 

 Scaphanocephalus (undescribed species of which are known to the 

 writer) from sea eagles in different regions are very closely related to 

 one another, as also are those of Bilharziella from seagulls and of 

 Hemistomum from herons. 



The trematode parasites from Australian marsupials are very 

 interesting in this connexion. Two species of Harmostomum from 

 Dasyurus and Perameles are very closely related to H, opisthotrias Lutz 

 from an American Didelphys, soclosely related that I am convinced that 

 they must be considered as being derived from common ancestors. 

 They thus afford some pretty convincing circumstantial evidence of 

 the phylogenetic relationship of the Australian and South American 

 marsupials. 



No less interesting are two new species of flukes, one from Dasyurus 

 and the other from the platypus, which have been described in Part 4 

 of the Proceedings of the Linn, Soc. N.S.W. for 1912, as representatives 

 of a subfamily intermediate in position between the Fasciolinae, flukes 

 typically parasitic in the higher mammals and the Psilostominse 

 parasitic in reptiles and birds. 



3.— THE SYRINX OF THE COMMON FOWL : ITS STRUCTURE 

 AND DEVELOPMENT. 



By A. 0. V, Tymms: 



[Published in Proc. Roy. Soc. Victoria, N.S. 25, 1913.] 



