LEI08ELLA. 



121 



fibres of the mpporting-sMeton are 0-U4 millim. thick and slightly knotty, cored 

 with large, irregular, longitudinally disposed spicule-fragments. The connect- 

 ing-fibres measure 0-01-0-02 millim. in thickness, are free from foreign bodies, 

 and form an irregular network with irregularly polygonal, angular^,^ meshes, 

 0-03-0-1 millim. wide. There are also foreign spicule-fragments scattered in 

 the ground-substance. 



Geogeaphioal Disteibution. — West coast of Australia : Freemantle, 

 W. A. (Bowerhank). East coast of Australia {Jukes, Lendenfeld). 



Leiosella levis, Lendenfeld. 



Eus^ongia levis, E. v. Lendenfeld, " A Monograph of the Australian Sponges. 



Part VI. The Genus Euspongia," Proceedings of the Linnean Society 



of New South Wales, vol. x. p. 536 (1885). 



Very irregular, ramified, horizontally extending sponges, which are composed 

 of numerous compressed, irregularly curved fronds, the free margins of which 

 are rounded and divided by broad incisions into lobose or digitate parts. These 

 fronds grow out from an extended base attached at several points. The sponge 

 attains a length of 200 millim., a breadth of 120 millim., and a height of 70 

 millim. The fronds are uniformly 8-10 millim. thick. 



The surface is smooth. With a magnifying-glass a regular network of 

 arenaceous ridges can be discerned in it. The oscula are chiefly situated on 

 the free margins of the fronds, where they form an irregular row ; a few are 

 also found on the faces of the fronds. They are slightly elevated, and measure 

 1 millim. in width. 



The living sponge is dirty greyish brown. Dry skeletons have a similar 

 colour, but are of a lighter hue. The dry skeleton is hard, only slightly com- 

 pressible, and elastic. 



The shagreen-Eke surface consists, as mentioned above, of a network of 

 ridges, chiefly composed of sand-grains and foreign spicule-fragments. These 

 ridges are about 0-07 millim. broad and not very prominent. The rounded 

 meshes are occupied by fine perforated membranes, which contain no 

 foreign bodies, and in each of which one, two, or three oval inhalant pores, 

 wlien dilated 0-02-0-03 millim. wide, are situated. Narrow canals 0-03 

 millim. wide lead, pervading the on an average 0-2 millim. thick skin, down 

 from these into extensive subdermal cavities, which consist of a network of 

 anastomosing tangential canals. The inhalants which arise from the floor of 

 the subdermal cavities are perpendicular to the surface ; their final ramifica- 

 tions measure 0-03-0-06 millim. in width, and extend for the most part longi- 

 tudinally. The ciliated chambers measure 0*037 millim. in diameter, are 

 spherical or pear-shaped, with a mouth 0-02 millim. wide, which leads into a 



