PLATE CLXIII. 



This shell, denominated by M. Lamarck from its native region 

 Scalaria Australis or Southern Wentletrap (Staircase shell) is a 

 species for which that writer was indebted to a communication of 

 the late secretary of the Linnaean Society, Alex. Mc.Leay, Esq. and 

 who had received it from New Holland some years before ; and we 

 have also, since that period, received the same species from Van 

 Dieman's land, through the hands of Mr. George Humphrey. ■ 



The description of this curious shell by M. Lamarck is very 

 accurate and satisfactory, but at the same time it must be acknow- 

 ledged that few readers are competent to form an exact conception 

 of a shell, or indeed of any object of natural history, unaccompanied 

 by a figure, so clearly as when accompanied by such an illustration ; 

 for in the latter case, the language of science, jointly with the deline- 

 ation of the pencil, becomes at once obvious, and leaves nothing 

 to be supplied by the imagination, either as to its appearance in 

 form, size, or colour ; it is, for this reason, we must presume, 

 that although the shell before us has nothing so materially in- 

 teresting in its appearance as to command attention, it will be 

 deemed of sufficient consequence to merit the elucidation we have 

 bestowed upon it, as an acquisition to the conchologist. Lamarck, 

 aware of its being a non-descript shell, has deemed it worthy of a 

 long and very minute description, and assuredly, therefore, we may 

 be allowed to trust that the figures in the annexed plate, the first 

 that have appeared, can scarcely fail to be considered useful as a 

 further illustration of the species. 



It will not escape the observation of the conchologist, that 

 Lamarck has placed this new shell in his system as a species of 



