THE 



8P N GE 8 



THE AUSTRALIAN MUSEUM. 



Phylum MESODERMALIA. 



Coelentera with a transgressing canal-system, with entodermal 

 collar-cells. The chief organs are of mesodermal origin. 



1. Classis CALCAREA. 



Mesodermalia with a skeleton composed of calcareous spicules. 



1. Ordo HOMOCffiLA. 



Calcarea the entoderm of which consists exclusively of collar- 

 cells. 



Familia ASCONID^. 



Sac-shaped Homoccela, often forming colonies, without a thick 

 mesoderm which the canals perforate. 



The Asconid® are identical with Haeckel's Ascones. Haeckel's genera are 

 adopted preliminarily. 



