18 



exact is the formation of a Helix imitated that Swainsou may reasonably 

 be pardoned for committing such an error, especially, considering he 

 had not the opportunity of seeing the clever little insect which thus 

 deceived him, and which is now known as "Swainson's mistake." It 

 may be interesting to Naturalists to know the further distribution of 

 these singular formations, which, hitherto, so far as I am aware, have 

 only been found in India and Brazil. I had not heard of their presence 

 in Tasmania before I discovered my first specimens, about nine months 

 since, in a tributary of the Upper Huon Erver, where thsy abound in 

 countless numbers. ' I had splendid opportunities of noticing the lively 

 little insect which is the sole proprietor and tenant of its house. They 

 are identical, in all respects, with those found in Brazil and India." 



The Secretary read the original description of these " cases" from 

 Swainson's Malacology ; also, a notice of the genus Thelidomus, from 

 Sowerby's Conchological Manual. Several specimens were placed under 

 a microscope of low power, and examined by the members. 



A letter from Dr. Milligan stating, inter alia, that he had forwarded 

 some books for the Society, was read. Among those specially mentioned 

 were Bewick's British Birds, 2 vols. ; Bewick's Quadrupeds, 1 vol.;. 

 Crania Btitannica (Dr. Davies), 1 vol., etc., etc. 



A paper ou the Land Shells of Tasmania, by Mr. W. F. Petterd, was 

 read by Mr. Stephens, who prefaced the reading by stating that the 

 writer was (unfortunately) not a member of the Society. The paper,, 

 however, had been forwarded to, and examined by the Council, and as 

 it was considered to be of sufficient value and importance to entitle it to 

 publication in the Transactions, he, by permission of the Council, 

 accepted the responsibility of introduciug it. Ou one particular point 

 the author deserved great credit. It was a failing of many collectors to 

 multiply exceedingly the number of species and even genera. Now, the 

 man who properly reduces the number of species was as great a bene- 

 factor to science, as the individual who on the other hand makes two 

 blades of grass grow instead of one, is to mankind. Mr. Petterd, he was 

 glad to say, could happily be included amoug the former class, as a great 

 number of instances could be pointed out in his paper, in which as many 

 as three, four, or five forms which had previously been described as 

 specifically different, had been comprised under the heads of single 

 species. 



The paper was one which admitted of little discussion, but it was- 

 remarked that, thanks to the labours of the Eev. -J. E. Tenison-Woods, 

 Mr, Legrand, Mr. Petterd, and Mr. R. M. Johnston, the Natural 

 History of Tasmania, so far as the land, marine, freshwater, aud fossil 

 shells were concerned, was in a very advanced and satisfactory condi- 

 tion. Some parts of the island were certainly still unexplored, but it 

 was probable that the greater number of specimens yet to be discovered 

 could be classed with forms already placed under specific heads. 



A vote of thanks to Mr. Petterd for his paper, and to the donors of 

 presentations, closed the proceedings. 



