210 
HORN EXPEDITION—MOLLUSCA. 
Family PaLudinid^. 
Bithinia australis, Tryon, sp. 
1865. Gahbia australis, Tryon, Araer. Jour. Conch., vol., i., p. 220, t. 22, f. 7. 
1875. Bithinia hyalina, Brazier, Proc. Lin. Soc. N.S.W., vol. i., p. 9. 
1881. Bithynia australis (Tryon), Tate and Brazier, Proc. Lin. Soc., vol. vi., 
p. 562 (inch B. hyalina, Braz.). 
1882. Bithinia australis, Smith, Proc. Lin. Soc., vol. xvi., p. 267, t. vii., f. 18. 
1882. Bithmia s^nithii, Tate, Trans. Roy. Soc. S. Aust., vol. v., p. 54. 
The genus Gahbia was founded on an erroneous interpretation of the 
characters of a fresh-water shell inhabiting New South Wales, the original 
diagnosis being as follows :—“ Shell like Amnicola, operculum paucispiral and 
calcareous.” Stimpson in his “ Researches on the Hydrobiina3” writes of it, p. 56, 
“ The figure of the unique species, G. australis, reminds us of Bythinia rather than 
any other genus, for in it the operculum is represented as decidedly concentric, 
although said to be paucispiral in the description.” Later, Brazier described a 
shell also from New South Wales as Bithmia hyalina. An examination of typical 
specimens of that species proves the correctness of the generic position assigned, 
but a comparison with the figure of Gabbia australis leaves no doubt as to the 
specific identity of the two ; therefore Tate and Brazier, in their check-list of 
Australian fresh-water shells, catalogue it as B. australis (inch B, hyalina). 
Smith, in his memoir on the fresh-water shells of Australia, describes as new a 
Bithinia australis, and quotes B. hyalina and Gabbia australis as different species. 
As the name of Smith’s species was thus pre-occupied in the genus, and judging 
from the figure of it I took it to be a different species, and renamed it B. smithii. 
On reconsideration of the figure and the text, it is probable that B. smithii is not 
distinct from B. australis, though the figure shows a slight angularity of the body- 
whorl not possessed by B. australis ; but as the text reads “ whorls very convex,” 
this may be a defect in the drawing. 
Mr. Brazier has communicated to me his opinion that B. schraderi, Fid., and 
B. australis are one and the same; but as Frauenfeld’s diagnosis. Verb, der 
Kaiser Kong. Zool.-bot. Gessellschaft in Wien, Yol. XII., p. 1153, 1862, was 
unaccompanied by figures and without comparison with any other species, except 
his B. vertiginosa, to which the same criticisms are applicable, and which may 
after all be only an elate form, of a composite species, the question of priority in 
