SPONGES FROM COASTAL BEACHES OF N. 8. WALES — 'WHITELEGGE. 97 



oscula is often three or four times greater than the edge of the 

 lamina. The margins of the oscula are generally prominent and 

 serrated. The serrations, when viewed in profile — by transmitted 

 light — are seen to be the terminations of dense longitudinal bundles 

 of fibres. Numerous smaller oscula are scattered over the surface 

 and along the margins ; they are not prominent, and often the 

 outer wall is incomplete, they are open externally, forming 

 deep grooves which are variable in length, sometimes extending 

 from the base to the summit; frequently near the summit^deep 

 grooves are present on both surfaces, with a thin central partition 

 between them. The surface exhibits numerous grooves besides 

 those which terminate at the margin; these are separated by high 

 irregular ridges, or a series of isolated columns, both of which are 

 apically clothed with numerous rigid villi from 1 to 3 mm. high. 

 The inhalent pores are very abundant, and are scattered all 

 over the surface ; their diameter is 1 mm. or less, and about the 

 same distance apart. A series of larger openings is present here 

 and there in the walls of the oscula and scattered over the ridges 

 of the lamina; they are very irregular in shape and rarely circular. 

 Texture in the dried condition, soft, elastic, but rather harsh to 

 the touch. Colour grayish to dark fawn. 



Skeleton net consisting of a close, fine reticulation. The main 

 fibres are rather sinuous, and cored with sand grains and spicule 

 fragments, the latter predominating; they are 0'05 mm. in dia- 

 meter, and from 02 to 05 mm. apart. The stouter secondary 

 connecting fibres are rather scarce; they are 0"03 mm. in diameter 

 and together with the primaries form an open network, with 

 elongated or angular mesh, about O'l by 0'2 mm. The spaces 

 between primaries and the stouter secondaries are filled with slender 

 much branched fibres, which form a very close reticulation ; the 

 fibres are generally about 0-01 mm. in diameter. 



Five specimens are in the collection from Lake lUawarra. This 

 variety is not uncommon on the coast near Sydney. 



EUSPONGIA ILLAWARRA, sp. 710V. 



(Plate xii., fig. 19). 

 Sponge flabellately expanded ; the base measures 200 mm. in 

 length and from 80 to 100 mm. m width, and has several points of 

 attachment. The upper margin is semicircular in outline, and 

 about 30 mm. in thickness in the centre, the lateral margins 

 become thinner and are subacute at their extremities. The height 

 of the frondose lamina is 140 mm. The whole of the margin and 

 several side processes are osculiferous at the summit. The oscula 

 are closely placed, and are separated by walls from 1 to 2 mm. in 

 thickness, the walls on the outer aspect of the margin are often want- 

 ing, and when viewed from above consist of about two-thirds of 

 a circle. At the vertex of the margin the oscula form a transverse 

 row ; laterally they decrease in number, and at the extremities 



