A Review of the Lakd Mollusca of Western Australia. 
1894 — TIel'x { Illifiiinda ) inconvictu Smith, Prop. Malac. Soc. (Loud.), A ol. 
I., p. 90, pi, A’ll., f. 10, June. Oscar Ranges, I'iO miles S.K. oi' 
King- Sound, North-AA'est Australia. 
Shell rather de]iressed, spire small, last whorl keeled at the peripherjg 
umbilicus not sealed. Apparentlj^ this sjioeie.s is restricted to the Oscar 
Ranges, Init there appears to be local variation as in adelition to a series ol 
fifteen “undei' stones” agreeing with the type, and obviouslj’ paratyjies and 
topotyiies, there is another .series of twenty-five ‘‘crawling about on the 
ground” which consists of unifornily smallei' shells. Their elevation varies 
a little, sometimes even more dejiressed than the lai'ger siieeics, at others 
eomiiaratively more elevated. These .show more colouring, being generally 
horn with slightly darker flaming above', a bi'oad brown band below the peri- 
phery, which fade.s basally into almost white. The shell is thinner, the lip 
a little more expanded, and the umbili('ns is a little more open. Aleasure- 
ments, breadth 17-18 min., height 11-12 mm. Th(‘se may be called R.o. perca 
subsp. nov., the typical shell measuring 18 mm. in breadth by 11 mm. in 
height. 
Rhagada astuta sp. nov. 
Plate lAh, fig. 17. 
Among the shells collected at Koohin Island, Yampi Sound, was one 
more flattened, and upon closer examination it was seen to he sculptured on 
the upper surface. 
Shell flattened, suhdiseoidal, sjflre little elevated, whorls rounded, month 
obliciuc, wide, open, but lips not flaring, the columella reflected almost clos- 
ing umbilicus, which is, however, still left open; almost a snbnodule seen 
basally on inner edge of li|). The apex worn, but ap|)arently finely striate, 
striae being seen at suture, the adult whorls sculptured by oblique radials 
above, the under surface smooth; tin* radials are vei'v numerous, regular, and 
distinct. Breadth 20 mm., height 12 mm. 
This specie, s is nearest osatrensis in form and ehai'acter, but is even 
flatter and is ca.sily distinguished by the upper sculpture. This feature is 
so alien to the true Tthagada that this species may prove very distinct, and 
in order to keep this point in view a new suligeneric name, Thetagada, with 
this as type, is introdneod. 
Geims PAEKHAGADA tredale 1938. 
1938 — Furrhagada Iredale, Austr. Zool. A^ol. IX., p. 114, Nov. 30. Orthotype' 
Thersites woodwardi Fulton. 
This grou]) comprises solid shells with short spire, broad body whorl 
and the month oi)en, the outer lij) expanded as a [hinge giving them a very 
distinct appearance. The type has the nmbiliens tightly sealed, but some 
of the s]iecie.s, though agreeing very closely in every other feature, leave the 
umbilicus .slightly open. 
A very curious ecological note states that one of the most solid was col- 
lected “on trees off the Limestone Caves.” The solidity of the tree-dweller 
can only be explained by the abundance of lime in their environment. 
Parrhagada woodwardi Fulton 1902. 
Plate IV., fig. IS. 
1902 — Thersites (lihagadd) u-nodwardi Fnlton, Proc. Alalac. Soc., (Lond.),. 
A^oi. V., p. 33, fig. in text, April. North- AYest Australia. 
This species was described by Fnlton from specimens sent him by B. R. 
AA^oodwnrd, without definite locality. Two specimens in the Perth Aluseum 
