540 a monograph of the australian sponges, 



Surface. 



The surface is conulated, the conuli attain a height of 1 mm., 

 and are 3 mm., apart. 



There is very little sand in the skin. The fields are subdivided 

 by a net- work of ridges as usual into secundary fields which contain 

 the pore-sieves. 



KiGIDITY. 



The skeleton is soft and not very elastic. The digitate processes 

 can be compressed to a tenth of their thickness by the weight of 

 1 kilogramm. 



Colour. 



The colour of the live sponge is dark bluish grey. This colour 

 is retained in spirits. 



Tlie canal system does not present any peculiarities. It is similar 

 to that of Euspongia officinals in every respect. 



Skeleton. 



The straight main fibres measure 0*09 mm., in thickness. They 

 are about 3 mm., apart. This is the reason why the sponge is so 

 soft. 



They are cored by sand grains which average 0-02 mm. The 

 foreign bodies are scarce and scattered, the surface is smooth. 



The connecting fibres measure 0-09 in thickness. They are as 

 thick as the main fibres and the meshes average a width of 0-3 

 mm. They are rather irregular. 



The specimens are not sufficiently preserved to enable me to 

 give an account of the histology of this species. 



Geographical Distribution. 

 INIauritius, (Yon Haast.) 



Bathymetrical Distribution. 

 Shallow water ] 



