106 CHALINOPSILLA. 



is light greyish yellow, elastic, very soft, and compressible. The interior 

 appears lacunose. 



The surface-skeleton consists of stoiiter primaries and very slender secondary 

 fibres. The latter are on an average only 0-02 millim. thick. The meshes are 

 0-15-0-2 miUim. wide. 



The supporting-sTceleton consists of a very regular network of horny fibres, 

 which are entirely free from foreign bodies. Main and connecting-fibres have 

 the same thickness — on an average 0*07 millim. The meshes are from 0'5-0"9 

 millim. wide, quadratic or triangular, with rounded corners. 



(This description is based on the Australian specimens examined by me, and 

 somewhat differs from Vosmaer's description.) 



Geographical Disteibution. — Mediterranean ( Vosmaer). 

 North coast of Australia : Torres Straits (Lendenfeld). 



Chalinopsilla radix, n. sp. 



Forming a dense and low bushy mass of straight, erect, cylindrical branches, 

 which grow out from the upper extended end of a short peduncle. The 

 sponge attains a height of 70 millim. and a breadth of GO miUim. ; the branches 

 are 5 miUim. thick, and rounded at the ends ; they are occasionally slightly 

 ramified, but never coalesce with each other, so as to form massive fan-shaped 

 or reticulated structures. The surface is smooth. The oscula are small, 

 circular, 1 miUim. wide, and scattered over the whole of the surface ; gene- 

 rally they are arranged in longitudinal rows, which may contain one or more 

 series of oscula. The colour of the living sponge is light grey, with an orange 

 tint ; this tint is not always observed, and may be due to the presence of 

 embryos, which are reddish. The skeleton is hard and cannot be compressed 

 between the fingers more than one fourth or one third. The living sponge is 

 softer. 



The surface-skeleton consists of a network of simple, unbranched fibres con- 

 necting the termini of the main fibres. There are no secondary fibres. The 

 fibres are, on an average, 0-03 millim. thick and widened at the ends, where 

 they join the ends of the main fibres. The meshes in the network of the 

 surface-skeleton are mostly triangular and, on an average, 0*2 millim. wide. 



The supporting-skeleton is free from foreign bodies. The main fibres are 

 0-06 millim. thick and on an average only 0-25 millim. apart. The connecting 

 fibres are very short, simple, and very regularly situated, always perpendicular 

 to the main fibres ; they are 0*035 millim. thick and 0-5 millim. apart. The 

 meshes of the network are rectangiJar, 0*5 millim. long and 0'25 mUlim. broad ; 

 their longest diameter is situated longitudinally, parallel to the main fibres. 



Geogeaphical Disteibution. — East coast of Australia {Eamsay). 



