BIOLOGY OF SNOWY RIVER AREA 167 



Genus ISIDORELLA Tate, 1896. 

 Isidorella newcombi (Adams and Angas). 

 1864. Pkysa newcombi, A. Adams and Angas, P.Z.S. Lond., 1863, p. 416. 

 1939. Isidorella newcombi Adams and Angas. Gebriel, Mem. Nat. Mns. 

 Vic, XL, p. 117, pi. 2, fig. 22. 



Size of Type. — Length, 21; breadth, 14 ■6mm. 

 Type Locality. — Ponds of Mt, Margaret, Central Australia. 

 Observations. — A thin, ovate-globose brownish shell with finely 

 spirally-striated, whorls. 

 Locality. — 6 specimens (F 1900) Banool, (lelantipy. (A.Hodge). 



Isidorella newcombi Adams and Angas var. crebreciliata (Tenison 



Woods). L 



1878. Physa crebreciliata , Tenison Woods, Trans. Roy, Soe. Vie., XIV, p. 63. 

 1939. Isidorella newcombi (Ad. and Aug.) var. crebreciliata (Tenison 

 Woods), Gabriel, Mem. Xat. Mus. Vie., XI, p. 119, pi. 2, fig. 25. 



Size of Type. — Length, 15; breadth, 7mm. 



Type Locality. — Oaulfield, Victoria. 



Observations. — On this form Hedley remarks, "There are on 

 the body-whorl about thirty-two spirals of line cilise decussated by 

 fine, close longitudinal lamella'. The latter as in the case of I. new- 

 combi, rise round the suture into a sort of ruff, or collar." 



Locality. — 10 specimens (P 1901) dam Rockbank; 18 speci- 

 mens (F 1902) Little River; 1 specimen (F 1912) Banool, Gelan- 

 tipy. 



Latnellibranchiata 



Family CYCLADIDAE 



Genus Pls'lDIUM Pfeiffer, 1875. 



Pisirfiitm etheridgii E. A. Smith. 



1882. Pisidium etheridgii Smith, Journ. Linn. Soe. Conch., Zool., XVI, p. 

 306, pi. 7, fig. 35. 



1939. Pisidium etheridgii Smith. Gabriel, Mem. Nat. Mns. Viet., XL, p. 

 129, pi. 4, fig. 37. 



Size of Type.— Length, 5-5; breadth, 6-5; diam., 3-5mm. 



Type Locality.— Y an Yean Reservoir, Plenty District, Victoria. 



Observations. — The smallest Victorian freshwater bivalve. 

 Smith (loc. cit.) remarks: "Umbones rather prominent, with the 

 young shell forming a more or less distinct apical cap. Concen- 

 tric strige very fine. Not unlike the European P. casertanum, but 

 rather less inequilateral." 



Locality.— o specimens (F 1892) dam Rockbank (2,800 ft.) ; 

 17 specimens (F 1898) Sandy Swamp (4,500 ft.) Rockbank. 



