72 



698 ; Paludestrina Legrandiana, Brazier, loc. cit. p. 699 ; 

 Amnicola Petterdiana, Braz. Proc. Linn. Soc. N". S. Wales, vol. 

 1, p. 19 ; Bythinia Legrandi, Tenison- Woods, Proc. Eoy. Soc. 

 Tas. 1875, j^. 76 ; Bythinia imicarinula, nobis, loc. cit. p. 71 ; 

 Bythinella Legrandiana, nob. op. cit. 1878 ; BytJdnella nigral 

 nob. loc. cit ; Bythinia unicarinata, Johnston, op. cit. Marcb, 

 1878; Bythinella Legrandiana, Johnston, loc. cit; Paludestrina 

 Legrandiana, Johnston, loc. cit. ; Bythinia Tasmania, Proc. 

 Eoy. Soc. Tas. 1865, p. 7*7 ; Bythinella Tasmania, Johnston, 

 op. cit. March, 1878. 



I have also to amend the diagnosis of Tatea Huonensis, 

 nobis. Animal with a broadly ovate foot, truncate nnder the 

 head, with lateral sinuses ; muzzle reddish brown with color- 

 less lip ; tentacles long subulate, colorless, encircled with 

 brown near the tip. Operculum subcalcareous, j)auci-spiral, 

 with a vertical submarginal claw. 



With regard to the genus Amnicola, I have already given 

 my reasons for regarding this as a purely American type. 

 Its history is this : in 1840 Messrs. A. A. Gould and Halde- 

 man in their supplement to a monograph of the Limniadcs 

 cited the genus in these terms : — Head j^roboscidiform, shell 

 like Paludina, operculum corneous and subspiral. No species 

 was taken as a type. Dr. Gould in his work on the Inverte- 

 brata of Massachusetts subsequently defined the genus and 

 took as a type the Paludince of few whorls. Mr. Stimpson 

 published an essay on Hydrobinse in 1865, and at p. 13 gave 

 a figure of the operculum of American Amnicolas, showing 

 that they possess peculiarities of structure which are found 

 in American freshwater shells only. Mons. P. Fischer, in 

 the Jour, de Conchyl. for 1878, vol. 18, p. 135, considers that 

 the genus must be entirely restricted to American species, 

 and in this opinion he is, I believe, followed by most con- 

 chologists. 



