4. MOLLUSCA OF TASMANIA. 
the continental shelf has been fairly well worked down to a 
depth of 100 fathoms, resulting in a large number of species 
new to science being taken and described; whilst perhaps an 
equally large number of described species inhabiting similar 
depths in New South Wales and South Australia have been 
identified. Most of the above will be found recorded as fol- 
lows:——First, by Hedley and May in Records of the Aus- 
tralian Museum, 1908; and subsequently by myself in Papers 
and Proceedings of the Royal Society of Tasmania for 1908, 
1910, 1912, 1915, and 1919.. On the other hand, there 
have been some reductions, as I have weeded out certain 
species appearing on our lists from old and doubtful records, 
the occurrence of which has not been confirmed after a further 
period of twenty years’ investigation. These species include 
several Southern Australian shells, some of which it is pos- 
sible may yet be reinstated. In this list I have catalogued, 
with extremely few exceptions, only those species of which 
I have seen authentic Tasmanian specimens, so that whatever 
changes may in future take place in nomenclature, at least 
the species themselves may be relied on as being inhabitants 
of the State and its surrounding waters. I have here included 
the whole of the mollusea—marine, land, and freshwater—as 
this will render the work much more complete, and all of these 
sections have now been well linked up; the two last are not 
likely to be much added to, but with regard to the marine, 
it cannot be doubted that systematic dredging on the unex- 
plored parts of our coast-line would add very considerably to 
our fauna, but such an examination may belong to the distant 
future. 
The New South Wales list, above referred to, has been 
closely followed in its classification and general arrangement, 
and was an immense help in this compilation, because so 
very many of the species are common to the waters of both 
States. The total number of molluscan forms herein cata- 
