OF NEW SOUTH WALES. 55 



Notwithstanding, however, this apparently convincing evidence, 

 I ana indisposed to believe it possible that an animal so completely 

 shut up in a thick coriaceous unmuscular sac, can have any power 

 of external movement, nor is it likely that such a power would 

 be possessed by an animal whose whole life (except in infancy) 

 has to be passed firmly rooted to the bottom of the sea. I hope 

 that some one having the leisure and opportunity, will endeavour 

 to solve this problem. 



On some Australian Littorinid^. 



By the Rev. J. E. Tenison- Woods, F.L.S., F.G.S., Corr. Memb. 

 Linn. Soc. N.S.W., &c. 



We have in Australia and Tasmania certain coast shells which 

 are variously distributed in several genera by different authors. 

 They all resemble each other in this, that they are found for the 

 most part on rocks which are seldom covered by the tide. They 

 are not nacreous. They have a horny operculum, with a 

 marginal nucleus and few whorls, and the animal has a small 

 round foot which has never tentacular filaments like the Turbo, 

 Trochus, or Phasianella. They are generally widely distributed, 

 subject to very much variation, according to the locality where 

 they are found. This has led to the same shell being regarded 

 in different places as a different species, and the varieties also 

 have been regarded as different species. In order better to 

 understand the present state of our knowledge of these marine 

 mollusca, it may be as well to state the history of the genus, or 

 rather its classification. To Linneeus all these shells were Turbos' 

 and those which were known to Schrotter, Chemnitz, Gmelin, 

 Favanne, Born, Humphrey, and Lamarck, came under the same 

 generic appellation. In 1821 M. Baron Ferussac, in his large 

 and expensive work on the fresh water shells of France (so large 

 and so expensive that it was never finished), divided the genus 

 Paludina into five sub-genera. He gave the fifth the name of 

 Littorma (written also with one t, or two r's by various writers), 

 and included in that the common perry-winkle Turbo UUoreus of 



