SPONOIIDA. 377 



Gelliodes Jibidata, Rhizochalina singaporensis, var., and Clathria 



reinwardti, var. subci/Htidriai. Ectyonidae and Tetraetinellidaare 

 relatively the most rich in species in this subequatorial region, 12 

 out of the 17 species collected of the fust and 7 out of the 8 of the 

 latter group being obtained here. It is remarkable that the only 

 Siliceous species hitherto recorded with certainty from the locality, 

 so far as I am aware (A'< iwx/n>»gia /»(/< lliformis, Oraj - , 1'. X. S. 1S5S, 

 p. 221), pi. 12), has not appear* d on this occasion ; it was, however, 

 perhaps obtained from deep water, as its apparent affinity to Hali- 

 cnemia, Bowerbank, of the British seas would suggest, and no speci- 

 mens were obtained on this occasion from deep water (if such exists) 

 in Torres Straits. 



Of the other localities, Port Darwin on the north-west and the 

 eastern Queensland coast on the east have been the most productive. 

 As might have been expected from the wide extent of moderately 

 deep sea which separates Port Darwin from Torres Straits, there are 

 very considerable differences between their Sponge-faunas, although 

 a larger number of dredgings made at the former would probably 

 have reduced these differences. AVe find, however, the Iotrochota 

 {purpurea) so common at Torres Straits replaced by another spe- 

 cies, 1. baculifera; Gelliodes fibulata and Rhizochalina singaporensis 

 do not even appear ; the Ectyonidne, so far from being common, have 

 but a single species here ; and the llenieridaa, so poorly represented 

 at Torres Straits, have here 10 species. Only a few species are here 

 shown to extend across the Gulf of Carpentaria (Toxochalina foli- 

 oides, Rhizochalina canalis, Stelletta purpurea^) . 



The Arafura Sea represents a somewhat deeper area, but, as might 

 have been expected, shows affinities with Torres Straits on the one 

 hand and Port Darwin on the other ; 3 species of Rhizochalina and 

 2 Stelletta} are its chief representatives in the collection. 



The Queensland coast does not appear to be so rich in Sponges as 

 in Alcyonaria ; in particular, the absence of Tetractinellida and 

 almost total absence of Suberitidae characterizes the collections 

 obtained from this region. The occurrence either here or in Torres 

 Straits of the whole of the 1 2 species assigned to species described 

 by Lamarck is evidence in favour of the view that it was here that a 

 considerable proportion of the Sponges described by him as collected 

 by MM. Peron and Lesueur in the ' Mers Australes ' were obtained. 



Port Jackson shows peculiarities connected with its southern lati- 

 tude, producing two British Suberitidse besides South-Australian 

 species of Leuconia and Hircinia', still, it has some species in 

 common with Torres Straits. Six species range from the south to 

 the 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 those 

 divisions which seemed most in accordance with the present state 

 of our knowledge. Remarks on the characters of the different groups 

 will be found under their names ; in some cases (especially Ohdli- 

 nidai, Desmacidinidw) important modifications in scope or characters 

 seem required by the results of the present collection. 



