STTLOTELLA. — EHIZOCHALINA. 187 



at one end, and simply rounded at the other ; they hardly taper at all towards 

 the rounded end. The thickest part of the spicule lies nearer to the pointed 

 than to the bluut end : the latter often appears slightly thickened and divided 

 from the body of the spicule by a hardly perceptible constriction. 



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

 N. S. W. {Lendenfeld). 



Stylotella aplysilloides, n. sp. 



Small and incrusting sponges, which extend horizontally to a length of 150 

 mUlim. and attain a height (thickness) of 5 mUlim. From the upper smooth 

 surface conic protuberances arise, on the summits of which the circular oscula 

 are situated, which measure 2-4 millim. in width. Vertical oscular tubes lead 

 down from them into the body of the sponge. 



The sTceleton consists of a network composed of spicule-bundles. The fibres, 

 which extend longitudinally and which are to be considered as main fibres, are 

 composed of pretty regularly situated and closely packed parallel spicules. The 

 bundles which connect them are not so pronounced, and it is often difficult to 

 say whether these main fibres are connected by secondary fibres or whether 

 they are only held together by the spicules scattered abundantly in the ground- 

 substance. The spicules are straight or very slightly curved styli, 0-13 millim. 

 long and 0-06 millim. thick. They are perfectly cylindrical, of uniform thick- 

 ness throughout ; one end is sharp and abruptly pointed, the other simply 

 rounded off. 



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

 N. S. W. {Lendenfeld). 



SubfamHia PHL(E ODICT YI N^. 



Heterorrhaphidse which consist of body and fistulee, with a stout 

 spicular rind. Megasclera oxea or strongyla. Microsclera absent 

 or when present sigmata. 



Genus RHIZOCHALINA. 



Massive Heterorrhaphidse with hollow roots and fistulse. Spi- 

 cules in bundles. 



