720 president's address. 



Rhizopoda and Infusoria which we find in the sea or in fresh 

 water here are nearly i-elated to, though very often clearly 

 distinguishable from, northern forms. Some peculiar forms have, 

 however, been observed, and T think that a student of any of the 

 groups of Australian Infusoria or Rhizopoda need not despair of 

 finding something new of importance and interest. Among the 

 Sporozoa a species of Myxobolus ( Myxosporidia) is common as a 

 parasite of certain frogs, and affords a good opportunity for the 

 investigation of the unknown life-history of that group. Sponges 

 are so abundant and varied that the working out of the embryology 

 which is thoroughly known in so few cases, ought to be a fruitful 

 subject of study. 



The Australian lower groups of worms have only been examined 

 as regards certain small and restricted groups — that which has 

 hitherto received most attention being that of the Land-Planarians. 

 The Rhabdoccela and the marine Polycladidcn and Tricladidce are, 

 with the exception of a few superficially described (by Stimpson 

 and Schmarda), entirely untouched ; and the same holds good of 

 the Trematodes and Cestodes, while I only know of three published 

 descriptions of Australian species of marine Nenierteans. Dr. 

 Cobb is expected to render a good account of the free-living 

 Nematodes ; but the parasitic forms are in the same position as 

 the Cestodes and Trematodes, and the same may be said of the 

 Acanthocephala. No Australian Archiannelida are known ; but 

 they and the Australian Enteropneusta are biding their time. 



Of the Ch^etopoda, on the other hand, we know many. Prof. 

 Baldwin Spencer and Mr. J. J. Fletcher are both occupied with 

 the terrestrial OligochaBta ; but the fresh-water Oligocholia, though 

 numerous and varied, have not yet received their due share of 

 attention. Of the Polychce.ta there are a number of families that 

 have not even been touched ; though, judging from what is 

 already known, there is not likely to be a wide divergence from 

 the fauna of other regions. Of the Leeches only three or four 

 species have been described out of a considerable number that 

 have been observed. A good deal still remains to be done with 

 the Gephyrea, though a few have been superficially described by 



