PAPERS READ. 



A MONOGRAPH OF THE AUSTRALIAN SPONGES 



By R. von Lendenfeld, Ph.D. 



Part IV. 



Plate I. to V. 



PRELIMINARY REPORT ON THE AUSTRALIAN MYXOSPONGI^. 



11. ORDO. MYXOSPONGI^. Haeckel (1). 



SPONGES WITHOUT A SKELETON, OR WITH SPHERICAL 

 POLYACTINELLID FLESHSPICULES. 



Sollas (2) has remarked in a recent paper that the Myxospongise, 

 as a group, containing Halisarca and Chandrosia, will eventually 

 have to be abandoned, he thinks that the diifereuce between the 

 Halisarcinse and Gumminse is so great that we cannot combine 

 them. The Halisarcidae, with the genera Halisarca Dujardin and 

 Oscarella Vosmser, are, according to Sallas, the sole true repre- 

 sentatives of the Myxospongise, wliilst the Gumminae should, 

 according to him, be placed in the neighbourhood of the Tetracti- 

 nellidge. 



It is very difficult to say whether the Gumminte represent 

 transition forms from any ancestral groups to the Tetractinellidse 

 or not, but it is quite certain that there is a vast difference 

 between the Gumminae on the one hand and Oscarella and Hali- 

 sarca on the other. 



I think it will approach the real relationship nearest, to establish 

 for these groups two Sub-orders within the Ordo Myxospongige, 

 as follows : — 



(1) E Haeckel. Die Kalkschwamme, eine Monografie. Band L, Seite 453. 



(2) W. T. Sollas. On the development of Halisarca lobularis, O.S. 

 Quarterly Journal of Microscopical Science, Vol. XXIV., ]}. 618. 



