24 
are represented but by different species. About 100 species of 1am- 
ellibranches at least have been recorded from the South-West alone. 
Probably our most important bivalve is the large pearl oyster Mar- 
gar itif era maxima , but this is confined to the North-West. The 
“sliipworms” ( Nausithoria sp.) have already been alluded to. 
A very large number of Gastropoda have been recorded and some 
are extremely common. Vermetus is responsible for great shelly 
tracts at Geraldton and the Abrolhos, but also occurs further .south, 
and can be seen on the beach near Fremantle. 
The Nudibranchiata appear to be well represented on our shores, 
and many of the species are new. Several specimens of the beautiful 
Hexabranchus imperialis have been captured at the Abrolhos, the 
locality where it Avas first discovered by Kent in 1897. Another 
interesting form is a species of Notodoris, recorded now for the 
first time from the Australian coast. The genus was instituted 
by Bergh for a single specimen, N. citrina from Rarotonga. Two 
other species have since then been made by Eliot for specimens 
from Zanzibar and the Maidive Islands. All the species are yellow 
in colour. It is stated in Eliot’s report that nothing is knowjn of 
the habits of these animals. Several specimens of Notodoris were 
obtained at the Abrolhos, and they may also belong to a new species. 
The animals were bright lemon yellow in colour, and no colouration 
could have been more conspicuous. Yet in all probability we missed 
many specimens, for they were living on a sponge of exactly the 
same colour as themselves, which formed encrustations on the under 
surface of great blocks of dead coral. The first specimen captured 
gave itself away by falling off a stone as it was being turned over. 
About 45 species of Polyplacophora are recorded up to date 
from the West Australian coast. 
Crustacea. — Very much work requires to be done in collecting 
and working out the Crustacea of Western Australia. Only about 
15 species of the Decapoda are recorded for W.A. in Haswell’s Cata- 
logue of the Australian Malacostraca in 1882. Very many exam- 
ples, however, must have been collected from time to time, and these 
have been named at various institutions, but unfortunately no list 
of these records is available. Our Abrolhos collections await inves- 
tigation, and nothing has yet been published by the Hamburg Ex- 
pedition. The only group that we can investigate with the literature 
at our disposal is the group Stomatopoda, thanks to the Monograph 
published by the Indian Museum, Calcutta. Upwards of seven 
species of this group have been recorded, and six of them are 
Indo-Pacific forms. 
Specimens of Nebalia sp. representing the group Leptostraca 
occur off Fremantle. What a remarkably wide distribution this 
genus has ! It was first found at Greenland, and it ranges from there 
to Chile and Japan, 
