224 THALASSODENtoEON. 



0-007 millim. thick. They are echinated by rather scarce, rough, or slightly 

 spined styli, 0-06-0-07 millim. loug and 0-006 millim. thick. 



Thalassodendron rubens, var. dura, nov. 



Large, branched, erect sponges, which attain a height of 700 millim. and a 

 breadth of 500 millim. , consisting of a bunch of numerous digitate, here and 

 there compressed and laterally, particularly at the branching points, distended 

 processes. The surface is slightly grooved. 



The skeleton consists of a pretty dense network of exceedingly thick fibres. 

 The irregular rounded meshes measure 0-1-0-3 millim. in width. The fibres 

 are on an average 0-2 millim. thick, and approximate in some places to form 

 perforated plates. Abundant, somewhat irregularly disposed, cylindrical styli, 

 0-15-0-25 millim. long and 0-004-0-007 millim. thick, are observed in the fibres. 

 These are more numerous in the longitudinal than in the transverse fibres. 

 The fibres are echinated by rough or slightly spined styli, on an average 0-07 

 millim. long and 0-006 millim. thick. The echinating styli are not abundant. 



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

 N. S. W. {Ramsay, Lendenfeld). 



Thalassodendron rubens, var. lamella, nov. 

 (Plate VII.) 



Large, erect, branched sponges, composed of a number of compressed, 

 laterally distended branches, extending in one plane, which anastomose occa- 

 sionally. The surface is slightly grooved. 



The skeleton consists of a network of irregularly curved fibres, on an average 

 0-08 millim. thick, which contain very irregularly disposed styli, 0-16 millim. 

 long and 0-006 millim. thick. The fibres are echinated by slightly spiny and 

 blunt styli, 0-06 millim. long and 0*006 mUlim. thick. These are pretty scarce. 



GrEOGRAPHiCAL DISTRIBUTION. — East coast of Australia : Port Jackson, 

 N". S. W. (Ramsay, Lendenfeld). 



Thalassodendron paucispina, n. sp. 



Large, irregular, digitate sponges, the processes of which are branched, com- 

 pressed, and expanded more or less in a plane, so that the whole sponge attains 

 a somewhat flabelliform appearance. 



The skeleton consists of longitudinal main fibres 0-1 millim. thick, which are 

 on an average 0-26 millim. apart, and joined by mostly simple transverse 

 connecting-fibres 0-07 millim. thick. In both pretty abundant and rather 



