144 THOEECTA. 



The oscula are confined to the concave side of the lamellar sponge, l'5-3 

 millim. wide, very abundant, and 2 millim. apart. The specimens from the 

 Northern localities are more open, flabelliform ; those from Port Jackson and 

 Port Phillip more caliculate. 



The dry skeleton is reddish brown and stiff. 



The skeleton consists of smooth or uneven main fibres 0*13 millim. thick, 

 which contain very few and scattered foreign bodies. They are about 1 millim. 

 apart. The connecting-fibres are 0-1 millim. thick, simple, slightly branched, or 

 attached to the main fibres by two roots. The meshes are irregular or mostly 

 square, 0'8-l*2 millim. wide. 



Geographical Distribution. — North coast of Australia : Northern Terri- 

 tory, S. A. (HaacJce). South coast of Australia : Port Phillip, V. {Lendenfeld). 

 East coast of Australia : Port Jackson, N. S. W. {Lendenfdd) ; Bellinger River, 

 N. S. W. {British Museum Coll.); Broughton Island (Bmnsat/). 



Thorecta exemplum, var. secunda, Hyatt. 



Spoyigelia rectilinea, var. tenuis, A. Hyatt, " Revision of the North- American 

 Poriferse. — Part II.," Memoirs of the Boston Society of Natural History, 

 vol. ii. p. 537 (1877). 



Stelospongus flabelliformis, var. latus, H. J. Carter, " Description of Sponges 

 from the neighbourhood of Port Phillip Heads, South Australia," Annals 

 and Magazine of Natural History, ser. 5, vol. xv. p. 305 (1885). 



Pedunculate, regularly cup-shaped sponges, which attain a height of 250 

 millim. The peduncle is conical, extending above, and measures in large 

 specimens at the base about 4 millim., and at the upper end 10 millim. in 

 thickness. 



The upper cup-shaped part, the body proper of the sponge, is generally 

 broader than high, and attains a width of 250 millim. The margin of the cup 

 is pretty regularly circular, even or undulating. The wall is very thick below, 

 and thins out towards the margin. The cavity of the cup is very shallow. 

 The outer surface is uneven, often pitted ; the inner surface smooth. The 

 oscula are 2-3 millim. wide and confined to the inner side of the cup. The 

 largest are situated at the base, and they become smaller as we approach the 

 margin. At the base the oscula are 10-20 millim., near the margin only 4-6 

 millim. apart. 



The colour of the living sponge is pretty bright sulphur-yellow. 



The dry skeleton is soft and compressible, light brown. 



The sJceleton consists of knotty and irregular main fibres 0*08 millim. thick, 

 which are free from foreign bodies, and curved or straight connecting-fibres, 

 about 0-6 millim. thick. The meshes are irregular, 0*5-1 millim. wide. 



