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matter at Fremantle. This is an excellent example of the most 
unexpected kind of connection between two subjects very rarely 
associated with each other — marine biology and engineering. The 
larvae of Nausithoria occur in the plankton. They die if they do 
not come up against a suitable material for attachment and boring. 
It does not take long for! penetration of timber, and three months 
after immersion specimens have been found some little distance in 
the wooden jetty piles. 
Let us now look at the other important lamellibranch on our 
coasts. The pearl oyster fisheries of Australia are probably the 
largest and best equipped at the present time in the world. The 
value of pearls and pearl shell is by no means inconsiderable, and 
the industry is without doubt a great asset to Australia. Now there 
is a great danger that fishing will be conducted without any scientific 
supervision until perhaps some serious trouble arises, such as, for 
example, has arisen in Ceylon. Then, of course, a scientific investi- 
gator will be called in. This, however, is more than shutting the 
stable door after the horse has gone ! The first thing that a marine 
biologist would have to do if called in, would be to make a study 
of the conditions under which pearl oysters had developed; you 
cannot call upon a biologist as you can upon a chemist or engineer, 
for problems in natural history are often peculiarly local. Besides 
there are very few marine biologists with any real knowledge of 
pearl oyster beds. Would it not be well worth the expenditure, 
therefore, as a kind of insurance, to have our pearl oyster banks 
studied in detail by scientists in conjunction with pearl fishers before 
there is any restriction in the supply? 
We want to know something about the enemies of the oysters on 
the North-West Coast, the breeding season, the deposition of spat, 
the cause of pearl formation, and the extent to which fishing is 
carried out. 
Hydrographical Conditions and the Marine Fauna. 
As more and more extensive collections of our marine animals 
are made and a greater knowledge of their distribution is obtained, 
we find that certain species occur only in the North, others are 
characteristically Southern, and others again may be very local and 
only found on certain types of sea bottom. We have a considerable 
stretch of coast line which runs roughly North and South — conse- 
quently extending through many degrees of latitude. This makes 
the study of geographical distribution very interesting, and it is still 
more so because the North-West Coast fauna is probably in many 
ways a connecting link between the Indian and Pacific faunas. 
Our large pearl oyster, Margaritifera maxima, does not extend 
down into Sharks Bay. Its place is taken there by a smaller species, 
moie valuable for its pearls than for its shell. True coral reefs are 
