REPORT ON THE WORM DISEASE AFFECTING THE 
OYSTERS ON THE COAST OF NEW SOUTH WALES. 
By Thomas Wiiitelegge, 
Fellow of the Royal Microscopical Society ; Zoologist , Australian Museum . 
At the request of the members of the Fisheries Commission, I, 
by permission of the Trustees of the Australian Museum’ 
recently paid a visit to Newcastle with a view to inquire into 
the so-called oyster disease, which is caused by the presence of a 
small marine worm, identified by Prof. Haswell, of the Sydney 
University, as Polydora ( fyicodore) ciliata (Johnston). On my 
arrival at Newcastle I was taken over the various oyster beds by 
Mr. Curan, the local Inspector of Fisheries, who did everything 
in his power to assist me. I am also indebted to Messrs. Gibbons 
and Anderson, two of the principal oyster lessees, for their kind- 
ness in providing me with boats and dredges. 
The Infected Area. 
Although the worm is very generally distributed, having been 
met with in various situations, from about half-tide line to moder- 
ately deep water, still the principal home of the worm appears to 
be on the mud flats about low-water mark. Tiie oysters from this 
region were invariably infected with the worm, particularly those 
which lay loose on the surface or partially buried in the mud. 
\Y hi 1st those oysters which were fixed to some solid substance, 
and elevated ever so little above the surface of the mud were com- 
paratively free from the pest. 
During my stay I examined about fourteen oyster beds, which 
I need not particularize, suffice it to say that the worst are the 
bare mud-flats and the artificial beds in deep water. The latter 
are composed of oysters collected on the banks of the river, and 
probably the majority were obtained from the mangrove flats, as 
they would be more easily gathered, inasmuch as they are not, 
in that locality, fixed to any solid substance. From an examina- 
tion of a very large series of these oysters, I am convinced that 
they were infested with the worm before thdir removal, as the 
evidence of disease was in nearly all cases deep-seated and below 
the lines of growth made after being laid down. The natural beds 
—only a short distance from the artificial ones — are fairly free 
from disease ; and, further, they appear to overcome the worm 
when attacked, quickly enclosing it with a thick layer of shelly 
matter before it has time to establish itself. From what I ascer • 
