74 NILS HJ. ODHNER, MOLLUSCA. 
FAM. LIMNAEIDAE. 
Isodora newcombi ApAams & AnaaAs. Perth, from water holes (*7/s 1911), 1 sp., 
h. 10 mm; wh. 4. In its hollow umbilicus, it agrees well with the figure given by 
Sowerby in Reeve’s Conch. Icon. 19 (Physa, pl. II, fig. 21). It has been found 
before near Mount Margaret, Western Australia (SmirH 1883), as well as in 8. Au- 
stralia (BEDNALL 1892). 
I. (Ameria) reevei Apams & Ancas. Noonkanbah, Kimberley district, in grass, 
1 empty shell, h. 6 mm (‘7 1911). Though best agreeing with the figure of this 
species in Reeve, Conch. Icon. 19, 1874 (fig. 40), it differs in having a somewhat 
narrower upper part of the last whorl. 
I. (Ameria) bonus-henricus Apams & Awnaas. Noonkanbah (°*/:2 1910), 1 dead 
shell, h. 5 mm, in its carinated penultimate whorl and the rounded last whorl with 
the strongly sloping aperture lip completely corresponding to fig. 29, pl. 6 of 
KE. A. Smiru, 1883. The species is recorded from Arnheim Land (Smirn). 
Planorbis essingtonensis KE. A. Smirn. In the Pandanus Spring near Noon- 
kanbah, Fitzroy River ('°/2 1911), many specimens, max. diam. 4 mm. A good 
description and figure is given by E. A. Smirn 1883. 
Ancylus australicus Tarr. Fitzroy River, in »billabong» ("/s 1911), 5 sps, 
max. ]. 2.9 mm. The position of the apex is somewhat variable inasmuch as it 
may be nearly median or more distinctly to the right; it is always situated at the 
posterior third of the shell. The anterior slope is a little more convex than in the 
figures of E. A. Smirnu (1883, pl. 7, figs. 36, 37), the shells a trifle more depressed 
and the apex directed to the right (not to the left, as in the figures). 
FAM. PALUDINIDAE. 
Paludina essingtonensis FRavenretp. Noonkanbah, Fitzroy River, in »billa- 
bong> (‘"/12 1910), 4 large and some small specimens, max. h. 24 mm, and many 
dead young ones. The species is found at Port Essington, in Victoria River, in 
Queensland and in tropical Australia (E. A. Suir 1883). 
FAM. UNIONIDAE. 
Diplodon wilsonii Lea. Fitzroy River, many sps, max. 1. 85 mm (°/s 1911). 
SoweERBY in Revve’s Conch. Icon. gives Port Jackson as the locality of this species, 
while Smirn (1883) mentions its occurrence in Central Australia (Mount Margaret and 
Umbum). Hepiry (1905) reports it from the Alberga River. In the nomenclature 
of Unionidae I follow Simpson (1900). 
