282 RECORDS OF THE AUSTRALIAN MUSEUM. 



Reniera lobosa, Lendenfeld. 

 Not represented in the collection. 



Petrosia hrbes, Lendenfeld. 



This species agrees with the diagnosis, but the latter is deficient 

 as regards the spicules present. Besides the " stout and large 

 oxystrongylote spicules with blunt ends, which measure 0*22 mra. 

 in length and 0013 mm. in thickness," there are numerous 

 boomerang-shaped strongyla 0'06 to 09 mm. in length, and 

 0008 mm. in diameter ; also abundant slender oxea 0'15 to 0.22 

 mm. in length, and 00045 to 0006 mm. in thickness. 



Halichondria rubra, Lendenfeld. 

 This species has already been referred to the genus Ehaphisia.^ 



Halichondria mammillata, Lendenfeld. 



The type (No. 338), a spirit specimen, agrees with the descrip- 

 tion in every character, except the dimensions of the spicules. 

 The latter are described as " mostly straight, exceptionally, also 

 slightly, curved, sharp-pointed oxystrongyla, 0*25 mm. long and 

 0006 mm. thick." The spicules observed in situ in the type, 

 and also others obtained by boiling, measure about 01 mm. in 

 length and 0*004 mm. in diameter. The British Museum example 

 received under this name has the fibres densely charged with 

 foreign spicule fragments. 



Halichondria clathriformis, Lendenfeld. 



The type (No. 409) measures 130 mm. in height, and 60 mm. 

 in width. The specimen consists of two compressed branches, 

 joined at the base and also at the summit by short processes. The 

 branches are 20 mm. in their broad and 15 mm. in their narrow 

 diameter. The dermal membrane is smooth, and exhibits a series 

 of circumscribed areas, which are reticulated and porous ; these 

 are separated by narrow well defined non-porous spaces. The 

 oscula are few and scattered, and measure from 5 to 7 mm. in 

 diameter ; each has an elevated margin, and a well-marked cribri- 

 form structure within the aperture. Internally the sponge presents 

 an open cellular appearance, not unlike that of a fine-meshed 

 species of Euspongia. The texture is soft, tough, and elastic ; 

 the colour yellowish stone. The skeleton consists of a series of 

 well-defined horny fibres, about O'l mm. in diameter; these are 

 connected by numerous secondaries, which rarely exceed 0"5 to 

 0"7 mm. in diameter ; both are charged with very numerous 

 spicules. Each spicule appears to have its own coating of spongin, 

 and I found it most difficult to reduce the fibres by boiling in 



2 Whitelegge— Rec. Aust. Mus., iv., 2, 1901. 



