PRELIMINARY NOTE > 
ON 
TH E (eB as 
(Leptoplana australis ), 
A species of Dendrocoelous Turbellarian Worm, destructive to Oysters. 
By DAVID G. STEAD, 
Naturalist to the Board of Fisheries for New South Wales. 
In the waters along the coast of New South Wales are to be found 
a number of species of marine worms belonging to the order of 
Turbellarians. These are related to the familiar objects known as 
“Fluke-worms”; but, unlike the latter, are free-swimming and 
non-parasitic in habit. They are most abundant in rocky situa- 
tions, or in the vicinity of loose boulders. From the popular stand- 
point, perhaps these would hardly be recognised as worms, as they 
are flat, thin, slimy objects, normally oblong or ovate in shape. 
The shape, however, is exceedingly variable, according to the situa- 
tion in which the worms find themselves. In some of the species, 
the same individual may now be long and narrow, while a little later 
it may be almost circular in outline. Some of these Turbellarians 
are extremely beautiful in color. 
The subject of this preliminary note, Leptoplana australis, which 
is, perhaps, the most common form, belongs to the division of 
Dendrocoelous Turbellarians, so-called because of their highly- 
branched and tree-like intestinal canal (which shows whitish, and is 
clearly visible through the skin of the lower surface). This species 
is to be found at all times, in greater or lesser abundance, in the 
lower (and salter) parts of our estuaries and harbors, where it 
will be found adhering closely to the rocks or loose stones, usually 
in some sheltered position, such as the lower surface, or in cracks 
