82 HALICHONDRIA. — RBNIOOBALrKA. 



Halichondria clathriformis, n. ep. 



Sponge lobose, massive, attaining a height of 250 millim., erect, attached by 

 a small base, with very large and conspicuous oscula, 10 millim. wide, which 

 lie scattered on the summits of the lobes, and a smooth surface. 



The slceleton consists of bundles of loosely packed spicules, which are con- 

 nected by very numerous others, scattered in such a way that the whole often 

 appears like a dense mass of irregularly disposed spicules. Spicides : oxystron- 

 gyla, sliglitly curved in the middle and very slightly tapering towards the ends ; 

 the ends are somewhat rounded, and from them a very narrow and sharp 

 spine projects, which lies axially and renders the spicule sharp-pointed. Th© 

 spicules are 0-33 millim. long and 0-011 millim. thick in the centre; the ter- 

 minal spine is 0*006 millim. long. 



Geographical Distribittign. — East coast of Australia : Port Jackson, 



N. S. W. (Lendenfeld). 



Genus RENIOCHALINA, n. gen. 



Lamellar, thin, branched, more or less flower-shaped Renierinae., 

 with smooth surface and a fibrous skeleton ; the spicules are 

 partly embedded in spongin. 



Reniochaliua stalagmitis, n. sp. 



The sponge is attached by a small base. It consists of a much-folded 

 lamella, about 2*5 millim. thick, which rises from the base of attachment 

 upward and outward, thus giving to the sponge the appearance of a broad 

 cone ; the interior of the cone is filled with the meandric windings of this lamella 

 and with secondary lamelte which are attached to it. From the upper free 

 margin lobose and digitate processes arise, and the whole attains more or less 

 tlie shape of a flower. The sponge is of dark colour in the living state. The 

 surface is roughened by the projecting skeleton-spicules. The oscula are 

 small, numerous, and scattered all over the surface. 



The sl-cleton consists of thi-ee systems of fibres — one longitudinal extending 

 from the base to the margin of the lamellae, the second transverse, and the 

 third perpendicular to the plain in which the two others extend. The fibres 

 belonging to the first two systems accordingly extend in the direction of the 

 lamella, whilst those belonging to the third system are perpendicular to it 

 and to the surface ; these fibres consist of bundles of somewhat irregularly 

 disposed spicules. The meshes between the fibres are square and on an 

 average 0-2 millim. wide, the fibres themselves are 0-045 millim. thick. The 



