NOTE* ON GEOGRAPHICAL DISTRIBUTION. 253 



known inhabiting Victoria, whilst New Zealand has five species. This 

 genus is limited to New Zealand and Victoria. Helix Tarauald, II. 

 reinga, and //. ophelia are North Australian species, said to have been 

 found also in New Zealand, but the first two are not in any of oiu' 

 collections, and the third one has not been compared from both 

 localities. Judging from the hypothesis of a former land communication 

 between New Zealand and Australia it is quite possible that the tln-ee 

 species are common to both countries. It would be of the highest 

 interest and importance to explore the high north of New Zealand for 

 land and fresh-water shells. The fresh-water shells Bulimus, Planorbis, 

 Ampliipeplea, and Limncea are found in nearly allied forms in New 

 Zealand and Australia, and Unio mutabilis, Lea., is also -said to inhabit 

 both. I have not seen any description or figure of this Unio. 



A good number of our shells point to a former land communication 

 with the islands of Lord Howe, Norfolk, Kermadec, New Caledonia, 

 Polynesia, and Phillipine Islands, but there remains much to be done 

 before we are able to make decisive conclusions. Mr. Charles Hedley, 

 of the Australian Museum, Sydney, has lately published a very good 

 and interesting paper on the land and fresh-water shells of Lord Howe 

 Island, in which he points out that the occurrence of the genus 

 Placostylus speaks eloquently of a recent land communication extending 

 on one side to New Caledonia and on the other to New Zealand. Our 

 genera of Diplommatina and liealia are also mentioned from this island, 

 and they are also found on Norfolk Island. With the Kermadec 

 Islands we have one species common, Vitrina (Helicarion ?) ultima, 

 Houss., which formerly has been found near Auckland. New Caledonia 

 has the genera Rhytida, Placostylus, Janella, AmpJdbola, Melanopsis, 

 Diplommatina, etc., common with New Zealand. Our genera Vitri- 

 noidea and Leptopoma (probably Lagochilus), show that land formerly 

 extended so far north as to the Phillipine Islands and very likely up to 

 A sia. 



A large number of the New Zealand genera are also distributed 

 oyer Polynesia, of which I would only mention Rhytida, Pitys, Torna- 

 tellina, Bulimus, Amphibola, Diplommatina, Cyclophorus, Realia, and 

 Hydrocena as the most important ones. 



Of many of our shells we do not know how far they are related to 

 similar forms of Polynesia, as the anatomy of the latter is unknown at 

 present. I am willing to undertake the work as far as time permits, if 

 only I could get the shells with their animals, either alive or preserved 

 in diluted methylated spirits, or our "national drinks," — whisky, brandy, 

 gin, could be used for the same purpose. I should be very thankful to 

 anybody Avho would kindly procure me land and fresh-water shells with 

 the animals from any part of Polynesia, Chile, Australia, Tasmania, and 

 New Zealand, and I am always ready to give the necessary instructions 

 for collecting, etc. 



This paper is by no means intended to be exhaustive on the 

 subject, I merely wish to point out how far the present knowledge of 

 our land and fresh-water shells may help "us in geological speculations 

 with regard to former extensions of land and water on the Southern 

 Hemisphere, and to show how much work remains to be done. 



