PETTERD : ON COLONISING LAND SHELLS. 97 



Mr. Gibbons states that it occurs at St. Helena, Madeira 

 and the Cape of Good Hope. 



Dr. Cox, in his ' Monograph of Austrahan Land Shells,' 

 quotes it as a new species under the name of H. Sydneyensis. 

 I have carefully examined vast numbers and cannot detect 

 any variation from the typical European form. Under the 

 name of H. cellariiis I include it in my 'Monograph of 

 Tasmanian Land Shells,' recently read before the Royal 

 Society of Tasmania. 



3. Helix costata. Suburbs of Sydney, New South Wales, and 



gardens about Hobart Town, Tasmania. Described by Dr. 

 Cox under the name of H. Alexandrce. About Hobart Town 

 it is often met with, and is becoming more plentiful and 

 diffused every year. 



4. Bulimus acutus. I recently had sent me some fine speci- 



mens of this shell collected near Melbourne, Victoria. 



5. Helix similaris. This has been obtained in great quantity 



in Guilfoyles Nursery, near Sydney, New South V/ales. It 

 appears to be a great wanderer, for Dr. Cox states that it has 

 been collected in Cuba, Brazil, Reunion, Mauritius, Natal, 

 Java, Bengal, China and the Sandwich Islands. 



6. Planorbis lacustris. In the freshwater streams near Mel- 



bourne, Victoria, this shell is plentiful. It is a highly 

 polished, yellow variety. It is difficult to account for its 

 introduction; doubtless the land species have been imported 

 among soil with plants, but I cannot understand how the 

 freshwater shell could find its way to the antipodes. 



7. Limn^a stagnalis. I was informed some years ago that 



the common large LiinncBa in the streams around Hobart 

 Town was this European species imported. It certainly 

 resembles it in a most striking manner, and 1 think eventually 



J.C, li., April, 1S79. P \ 



