546 A MONOGRAPH OF THE AUSTRALIAN SPONGES, 



specimen attains a size of 70 mm. in length, 40 mm.in bi-eadtli and 

 20 mm. in height. The thickness of the lamellose sponge rarely 

 exceeds 14 mm. 



Surface. 



The surface of the sponge is perfectly smooth in the living 

 state. There are, however, in hardened specimens, which always 

 shrink a little ; slight depressions in the fields between the termi- 

 nations of the main fibres in the skin, which then, of course, 

 appear as conuli. (Plate XXXVIII., fig. 1). 



A few tangental connecting fibres radiate from the terminations 

 of the main fibres and these support the skin in which they 

 extend, they are not difierent from the fibres in the interior. 

 There are only very few foreign bodies in the skin, so that the 

 slightly raised ridges on the surface, which form the usual network 

 dividing the pore-sieves from each other, do not appear like dense 

 masses of sand, as in some of the species described above. The 

 few foreign bodies ai-e scattered irregularly over the surface, they 

 are always tangentally disposed, foreign siliceous spicules often 

 quite unbroken. (Plate XXXVIIL, fig. 1.) In the pore-sieves 

 there are a great many small pores. (Plate XXXVIII., fig. 3). 



The oscula are small and numerous, scattered irregularly over 

 the surface or also grouped in lines. They are circular and 

 measure 1 mm. in diameter. They appear very slightly raised 

 over the surface. 



Rigidity. 

 This sponge is very hard and elastic. A lamella, 10 mm. in 

 thickness and 400 m mm- large is compressed, 3 mm, by the 

 weight of one kilogramm. 



Colour. 

 In the living state this species is of a greyish rose colour. In 

 spirits it appears darker grey on the surface and lighter grey in 

 the interior. Tlie dry skeleton is light brown. 



