102 RECORDS OF THE AUSTRALIAN MUSEUM. 



The sponge is unusually flabellate, and higher than wide ; 

 generally there is a short compressed peduncle, which is often 

 sharply defined, but occasionally it gradually merges into the 

 lamina ; the latter varies in outline, but in most cases it is sub- 

 orbicular. The surface invariably exhibits elevated, rounded 

 ridges, which indicate the course of the oscula tubes ; they are 

 strongly marked near the margin, at least on one side, and 

 frequently on both. There is also a series of shallow depressions 

 scattered irregularly over the general surface. In some specimens 

 the main lamina gives off at right angles small oscula bearing 

 ridges or lamellae, which often attain to nearly the size of the 

 original frond. The oscula are from 1 to 5 mm. in diameter ; 

 they occur at regular intervals along the upper border, and some- 

 times they surmount a prominent ridge or lobe at the sides of 

 the lamina. The whole surface of the sponge exhibits a great 

 number of inhalent pores 0'6 to 0"8 mm. in diameter, and about 

 1 mm. or less apart. Numerous branching grooves are present 

 here and there, being well marked at the base and also near the 

 margin ; their width is usually under 1 mm. Texture fine, 

 very dense, hard and highly elastic. Colour, bright yellowish- 

 brown. 



The skeleton is arranged as in Coscinderma lanuginosa, Carter ; 

 the fibres are, however, stouter, especially the secondaries, and 

 the mesh is much finer ; the main fibres are interruptedly cored 

 with smaller foreign bodies. These consist of spicule fragments 

 and sand grains ; generally they are arranged in a single row, 

 and only occupy about one-third of the dense and strongly lami- 

 nated horny fibre. The primary fibres are about 0*15 mm. in 

 diameter, and from 0-2 to 0*4 mm. apart. The longitudinally 

 arranged main fibres of the central region are usually without 

 foreign bodies ; the stouter transverse fibres have an interrupted 

 core, which becomes continuous as the surface is approached. 

 The connecting fibres are free from deposits of sand grains ; they 

 vary from 0*04 to 0"08 mm. in diameter, and their distance apart 

 rarely exceeds 0*2 mm. in the centre, and from 0"5 to O'l mm. 

 near the surface. 



Specimens of this species have been compared with examples 

 of Coscinoderma lanuginosa, Carter, from Port Phillip, and also 

 with a mounted section from a specimen in the British Museum. 

 It exhibits several important dift'erences, which may be enumerated 

 as follows : — The texture is closer, the inhalent pores are smaller ; 

 the oscula are more numerous, less in diameter, and never project 

 so as to give a serrated outline to the margin. The largest 

 specimen measures 300 mm. in height, 250 mm. in width, and 

 from 7 to 25 mm. in thickness; the peduncle is 60 mm. in length, 

 10 mm. in thickness at its juncture with the frond, and about 

 40 mm. at the base. A smaller example is 180 mm. in height, 



