THE FRESHWATER MOLLUSCA OF VICTORIA 
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Genus PISIDIUM Pfeiffer, 1875. 
Pisidium etheridgii E. A. Smith. 
(PI. IV, Eig. 37.) 
1882 Pisidium Etheridgii Smith, Journ. Linn. Soc. Lend., Zool., xvi, 
306, pi. 7, fig. 35. 
1887 Pisidium Etheridgei Smith. Tate, Tr. Roy. Soc. S. Aust., ix, p. 94. 
1893 Pisidium Etheridgei Smith. Adcock, Hand-List Aquatic Moll. S. 
Aust., p. 12. 
1894 Cyclas (Pisidium) etheridgei Smith. Whan, Geelong Nat., iv.. No. 
. . 1.0- P- 9- . . 
1936 Pisidium etheridgei Smith. Cotton, S. Aust. Nat., xvii. Nos. 1-4, 
p. 85, fig. 47. 
Size of Type. — ^Length, 5 5 nun.; breadth, 6 5 mm.; diam., 
3 5 mm. 
Localities. — Van Yean Eeservoir (R. Etheridge) ; Port 
Fairy (Rev. Whan) ; Fall’s Creek Reservoir (Nat. Mus., 
Melb.) ; Mt. Baw Baw (J. Searle) ; Bangholme, Tarraville 
(T. Worcester) ; Blackburn Lake (A. C. McLaehlan) ; “The 
Sanctuary” at Lome, Studley Park (C. J. Gabriel). 
Vernacular Name. — Etheridge’s Pea Shell. 
Observations. — The smallest Victorian freshwater bivalve. 
Smith remarks: “Umbones rather prominent, with the young 
shell forming a more or less distant apical cap. Concentric 
striae very fine. Not unlike the European P. casertanum, 
but rather less inequilateral.” 
Family UNIONIDAE. 
Genus HYRIDELLA Swainson, 1840. 
Ilyridella australis (Lamarck). 
(PI. IV, Fig. 38.) 
1819 Unio australis Lamarck, Anim. S. Vert., Ed. 1, vi, p. 80. 
1836 Margarita (Unio) depressus Lea, Syn., p. 32. 
1843 Unio australis (Lam.) Hanley, Bivalve Shells, p. 192, pi. 21, fig. 25. 
1850 Unio balonnensis Conrad, Pr. Ac. Nat. Sci. Phil., v, p. 10. 
1856 U. shuttleworthi Kuster, Conch. Cab., Unio, p. 152, pi. 44, fig. 2. 
1861 U. philippianus Kuster, op. cit., p. 235, pi. 79, fig. 2. 
1868 U. moretonicus Reeve, Conch. Icon., pi. 24, fig. 118. 
1871 U. danieli Villa, Jour, de Conch., xix, p. 328. 
1882 U. bednalli Tate, Tr. Roy. Soc. S. Aust., v, p. 56. 
1882 U. australis Lam. Tate and Brazier, Pr. Linn. Soc. N.S.W., vi, 
p. 567. 
1882 Id. Smith, Journ. Linn. Soc. Lond., Zook, xvi, p. 309. 
1888 Id. Cox, Pr. Linn. Soc. N.S.W., iii (2), p. 1,253. 
1888 Id. Tate, Tr. Roy. Soc. S. Aust., xi, p. 69. 
