CLATHRIODENDUON. 215 



Genus CLATHRIODENDRON, n. geu. 



Desmacidonidse with exceedingly large tylostylote megasclera 



scattered in the ground-substance. The spongin-fibres of the 



supporting skeleton contain only few spicules. Echinating 

 spicules spined styli. 



Clathriodendron arbuscula, n. sp. 



The sponge has the shape of a tree all the branches of which are shghtly 

 compressed and flattened, 12 millim. broad, of uniform thickness through- 

 out, and tending upwards. The surface is conulated, and bears numerous 

 sharp and slender projections, which are on an average 2-5 millim. high. The 

 oscula are scattered and very small. 



The sleleton consists of a network of horny fibres, 0-05 millim. thick. The 

 meshes are elongate, longitudinally disposed, on an average 0-5 millim. long 

 and 0-3 millim. broad. In the axis of the horny fibres large styli are found 

 which attain a length of 0-35 millim., a thickness of 0-12 millim,, and which 

 form a single series in the fibre. The fibres are echinated by abundant blunt 

 and somewhat club-shaped styli, 0-084 millim. long and 0-011 milhrn. thick at 

 the base. The spines are numerous, stout, and about 0-004 millim. high. 

 The echinating styli are attached at an angle of 50° to the surface of the fibre ; 

 only a very small part of the spicule is imbedded in the fibre. In the ground- 

 substance styli similar to those in the fibres are met with. 



Geogkaphical Disteibution.— East coast of Australia: Port Jackson, 

 N. S. W. (Bamsay). 



Clathriodendron irregularis, n. sp. 



Sponges which coiisist of a few stout branches, arising from a small base 

 and tending upwards. These branches are 25 millim. thick, and consist of an 

 irregular reticulation, being perforated by oval holes and canals in every 

 dire^'ction. The whole sponge attains a height of 150 millim. The surface is 

 very irregular; the skeleton and spiculations are similar to those of the foregoing 

 species. 



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

 N. S. W. (i?rt»(Srf(/). 



