HOUTMAN ABROLHOS ISLANDS. 161 



purple Madrepora already mentioned, and tree-fungus-like growths of a 

 species allied to M. eorymbosa, forming great flat expansions 3-6 feet across. 

 Several large species of Holothurians abounded on the shore of the island, 

 and could be picked up by wading. Anemones, Ascidians, and Sponges 

 (calcareous and siliceous) abounded, and several Turbellaria were captured 

 under the stones. In fact we were able to make a very good general 

 collection here. A better place still on our first expedition was the eastern 

 shore of Long Island. The beach consists of large coral slabs thrown up by 

 the waves, and at low-water mark almost each slab was covered on its under 

 surface with a gorgeous array of organisms. Rarely have I met such 

 variety and colouring. A straggling brilliant lemon-yellow sponge was one 

 very evident specimen. After turning several stones over and noticing what 

 appeared to be pieces of this sponge falling off, it was discovered that the 

 falling pieces were nudibranchs resembling the sponge in both colour and 

 general appearance; The species belongs to the genus Notodoris, this being 

 the first record for the genus on the Australian coast. It was instituted by 

 Bergh for a 'single specimen of N. citrina from Rarotonga. Two other 

 species have been made by Eliot for specimens from Zanzibar and the 

 Maldive Islands. All three are yellow in colour. It is stated in Eliot's 

 report that nothing is known of the habits of these animals and further — 

 " With Mr. Gardiner's specimen is a piece of hard yellow sponge. There is 

 no note, but as the colour and consistency of the sponge closely resemble 

 those of the Nudibranch it is highly probable that the latter frequent it." 



It is interesting to find that this is actually the case and in an entirely 

 different region. Our specimens were always found associated with 

 the sponge. The Nudibranch moves about very slowly, so far as could be 

 observed, and apparently lives in the dark under coral blocks. 



A large number of different species of Brachyura occurred on the Long- 

 Island shore, amongst which may be mentioned the characteristic species 

 Liolphus platissimus. This peculiarly shaped and beautifully marked crab 

 was exceedingly common. It is an Indian form. Several specimens of the 

 Stomatopod Gonodactylus cldagra were also obtained under stones. 



Small macrurans of a species as yet not identified were common, and 

 specimens of at least two species of Alpheus were captured. The Echino- 

 derm collection contained chiefly large crinoids and asterids. The gorgonids 

 were represented by one species. 



On the western shores of West Wallaby Island collections were also made 

 on the reef-flat. Five or six species of anemones were to be seen here in 

 great numbers. The most abundant molluscs were Astralium sp., with 

 beautiful blue operculum (the species is common on the coast both north and 

 south of the Abrolhos latitude), and \ r ermettis. Large numbers of the 

 Siphonophore, Porpita, came in over the reef one afternoon. 



12* 



