226 PLECTISPA. 



the distal surface by smooth styU. The fibres in tlie interior are 

 often not echinated at all. 



Plectispa elegans, u. sp. 



The sponge consists of a reticulate mass of regularly cylindrical digitate 

 branches, which are on an average 5 millim. thick. The surface is pretty 

 smooth. 



The sheleton consists of main and connecting-fibres. The former measure 

 0*2 millim. in thickness and contain abundant styli, 0'16 millim. long and 

 0-006 millim. thick. The connecting-fibres form a dense network with rounded 

 meshes 0-03-0-15 millim. wide; they are on an average 0-07 millim. thick, 

 and contain scattered spicules similar to those in the main fibres. The super- 

 ficial fibres are echinated on the distal surface by fairly abundant smooth styli, 

 0-07 millim. long and 0-005 millim. thick. 



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

 N. S. W. (Ramsay). 



Plectispa arborea, n. sp. 



Dendritically ramifj'ing sponges, which attain a height of 300 millim. The 

 stem, which is clearly defined, is attached by an extensive basal plate, slightly 

 compressed, and about 8 millim. thick. The surface is rough. 



The sJceleton consists of an exceedingly dense network of fibres. The longi- 

 tudinal fibres are on an average 0-1 millim. thick; the others, which can be 

 regarded as connecting- fibres, measure 0-02-0-05 millim. The latter form a 

 network with polygonal meshes, 0-14 millim. wide. The longitudinal fibres 

 contain styli, 0-08 mdlim. long and 0-004 millim. thick, which are not very 

 abundant. Scattered spicules are also found in the connecting-fibres. The 

 fibres are echinated by very scarce smooth styli, 0-05 millim. long and 0-004 

 millim. thick. 



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

 N. S. W. {Lendenfeld). 



Plectispa macropora, n. sp. 



Small and teuder reticulate honeycomb-like sponges, which appear massive 

 or incrusting and attain a height of 40 millim. The meshes of the honeycomb 

 are very unifox^mly 3 millim. wide and regularly polygonal. 



The skeleton consists of a network of fibres 0-05 millim. thick, which are 

 liilcd wlLli slender straight or curved styli, 0-2 millim. long and 0-004 millim. 



