Report on the zoological collections made in the Indo-Pacific Ocean ...

.6P0NGI1DA. 377Gelliodes Jibulata, lihizochalina sin'japorensis, var., and Clathriareinwardti, var. subcijUndrica. Ectyonidic and Tctractinellida arerelatively the most rich in species in this siibequatorial region, 12out of the 17 species collected of the first and 7 out of the 8 of thelatter group being obtained hero. It is remarkable that the onlySiliceous species hitherto recorded with certainty from the locality,so far as I am aware (XenosjJOHgia patellifonnis, (iray, P. Z. S. 1858,p. 229, pi. 12), has not appeared ou this occasion ; it was, however,perhaps obtained from deep water, as its apparent affinity to Hallcnemia,Bowcrbank, of the Eritish seas would suggest, and no specimenswere obtained on this occasion from deep water (if such exists)in Torres Straits.Of the other localities, Port Darwin on the north-west and theeastern Queensland coast ou the east have been the most productive.As might have been expected from the wide extent of moderatelydeep sea which separates Port Darwin from Torres Straits, there arevery considerable differences between their Sponge-faunas, althougha larger number of dredgings made at the former would probablyhave reduced these differences. We find, however, the lotrocliota{purpurea) so common at Torres Straits replaced by another species,/. bacuUfera; OelUodes fifndata and lihizocludina singaporensisdo not even appear ; the Ectyonida;, so far from being common, havebut a single species here ; and the llenieridaj, so poorly representedat Torres Straits, have here 10 species. Onlj^ a few species are hereshown to extend across the Gulf of Carpentaria {Toxoclialina folioides,Rluzocludina cancdis, Stelletta purpurea')The Arafura Sea represents a somewhat deeper area, but, as mighthave been expected, shows affinities with Torres Straits on the onehand and Port Darwin ou the other ; 3 species of lihizochalina and2 Stellettai are its chief representatives in the collection.The Queensland coast does not appear to be so rich in Sponges asin Alcyonaria ; in particular, the absence of Tctractinellida andalmost total absence of Suberitidse characterizes the collectionsobtained from this region. The occurrence either here or in TorresStraits of the whole of the 12 species assigned to species describedby Lamarck is evidence in favour of the view that it was here that aconsiderable proportion of the Sponges described by him as collectedby MM. Peron and Lesueur in the Mers Australes ' ' were obtained.Port Jackson shows iieculiarities connected with its southern latitude,producing two British Suberitidaj besides South-Australianspecies of Leuconia and Ilircinia ; still, it has some species incommon with Torres Straits. Six species range from the south tothe north of Australia.Classification.—I have followed no one author in this matter.The subject is in a state of transition, and I have adopted thosedivisions which seemed most in accordance with the present stateof our knowledge, llcmarks on the characters of the different groupswill be found under their names ; in some cases (especially Chali-7iidce, Desmacidinidce) important modifications in scope or charactersseem required by the results of the present collection.