188 EHIZOCHALINA. 



Rhizochalina ramsayi, u. sp. 

 (Plate III.) 



Large spherical massive sponges, attaining a diameter of 250 millim., at- 

 tached by stout roots, arising from the lower side, to the mud of the sea- 

 bottom. These roots attain a length of 300 millim. and are repeatedly 

 branched. From the upper surface and the sides numerous fistular tubes, 

 with an average width of 4 millim. and a height of 35 millim., arise, which 

 stand close together and are parallel, all tending upwards. From the centre 

 of the upper surface 2-5 much wider and shorter tubes, 20 millim. wide and 

 only 25 millim. high, originate, the cavities of which are occupied by a reticu- 

 late structure. Both the large and the small tubes are oscular tubes, and their 

 terminal apertures oscula. The surface is, apart from these highly prominent 

 oscula, quite smooth. The colour of the living sponge is yellow. 



The skeleton consists of a network of spicule-bundles with regular oval meshes. 

 The ground-substance contains very few scattered spicules. The fibres are on 

 an average 0-12 millim. thick, and the meshes 0"14 millim. wide and 0*35 

 millim. long. The spicules forming the fibres are regularly longitudinally dis- 

 posed and closely packed. The spicules are not very sharp-pointed, generally 

 slightly curved, oxystrongyla, 0*15 millim. long and 0*007 millim. thick. 



Geographical Disteibution. — East coast of Australia : Port Jackson, 

 N. S.W. {Ramsay). 



Rhizochalina petrosia, n. sp. 



Massive lobose sponges, with smooth surface and scattered oscula, which are 

 on an average 2 millim. wide. 



The skeleton consists of bands of longitudinally disposed spicules. These 

 bands are irregular, 0-1-0-3 millim. thick. The spicules are very slightly 

 curved, cylindrical oxea, 07 millim. long and 0-015 millim. thick, with sharp- 

 pointed ends. 



Geographical Distribution. — East coast of Australia : Port Jackson, 

 N. S. W. (Ramsay). 



Subfamilia GELLIN^ffi. 



Megasclera oxea or strongyla. Microsclera always present— 

 sigmata. No rind or fistiilae. 



