INTRODUCTION. 111. 



represented in South Australia by several fine forms. The present 

 synopsis contains a complete list of all the species of terrestrial mollusca 

 known to exist in the island, with the exception of the Limacidce. There, 

 however, yet remains a considerable portion that has not been examined, 

 and although the number of species may be further augmented, I do not 

 anticipate any material deviation f i-om the forms herein recorded ; that is, 

 those that may be hereafter discovered will be species closely allied to 

 those already known. The range of many will probably be found to be 

 even more extended, and in the observation of the habits and charac- 

 teristics of the animals there yet remains a vast and almost untouched 

 field of research. From the western portion information is more par- 

 ticularly wanted, for there comparatively little has been done. The 

 extreme north and south have, I may say, been thoroughly examined ; 

 so that I do not think the central portion will add many to this list, 

 although its examination would increase our knowledge of the distribu- 

 tion, which to the truly scientific conchologist is of as much, if not more, 

 importance than the mere accumulation of numbers ; the tendency, I 

 regret to say, of the majority of observers is to look upon trivial variation 

 as of specific importance, and quite overlook the higher aim of the mor^ 

 philosophic naturalist. The total number herein recorded indigenous to, 

 and introduced into, the island is 79 species, belongmg to the following 

 genera : — Helix, 68 ; Bulhaus, 2 ; Vitrhia, 3 (?) ; Succinea, 2 (^jossibly 

 4) ; Truncatella, 4 (?). But this number will, in all probability, require 

 still further reduction, for the following are of doubtful specific distinc" 

 tion : — Du Cani, positura, Stephensi, plexus, Langleyana, questiosa 

 tranquilla, Sjnceri, and Vitrina Jumosa. Two species, H. hisulcata and 

 H. suhangidata, both large and conspicuous forms, are recorded as from 

 Van Diemen's Land, but I have not met with either, and I believe they 

 still remain unique in the British Museum collection, and two are 

 inti'oduced Europaan forms — H. cellaria and H. Pidchella. 



Of the total number (79) Dr. Cox has described 26; Brazier, 14; 

 Woods, 4 ; Beddome, 3 ; Pfeifi'er, 6 ; myself, 17 ; and the remainder by 

 Beeve, Tate, Johnson, Leach, Ferussac, and Kuster. The number ot 

 species that may be considered as generally distributed over the island is 

 20, of which number 10 extend in range to the mainland of Australia; 



