308 A MONOGRAPH OF THE AUSTRALIAN SPONGES, 



and smaller until a pedunculate pyriform sponge with numerous 

 Oscula on the apex is produced. (C. ex. tertia.) This variety- 

 is identical with some sponges described by Carter as Stelosponges 

 levis, Hyatt, etc., and also with Hyatt's Spongelia rectilinea 

 errecta. Finally in quart. (C ex. terminus) we find a pedunculate 

 pyriform sponge with a single terminal Osculum. This shows 

 how in various ways the same form may finally be produced, and 

 with what difficulties the study of the relationship of sponges is 

 beset, at the same time furnishing an example to Oscar Schmidt's 

 statements regarding approximating development. 



Geographical Distribution. 



North Coast of Australia, Torres Straits, Palm Tree Island 

 (Macleay.) 



Bathymetrical Distribution. 



Shallow water. 



28. GENUS AULENA. (1) NOVUxM GENUS. 



Auleninse, the body of which possesses the shape of a sponge-like 

 reticulation. In the intervals between the meshes of this network 

 a network of very fine membranes expands. The fibi'es of the 

 sponge network possess the usual structure of sponges. The 

 lacunose cavities between, which are pervaded by the membranes 

 mentioned above, have the significance of anti-chambers. They 

 are attached as it were to the outer surface of the true body of 

 the sponge, and so form a vestibule. 



The skeleton consists of a network of very fine horny fibres 

 which never contain foreign bodies, are solid and transparent ; 

 and show a slender axial thread and stratified horn substance 

 around it. 



In the vestibule portion of the sponge the meshes of the net- 

 work of these fibres are very wide. In the true body of the 

 sponge about four times as small. In the true body of the sponge 



(1) Aukna from dv\rj the vestibule or antichamber ; with antichambers. 



