Sponges from South Australia. 219 



sively arenaceous in Dysidea. But, as this diagnosis alone 

 applies more or less to all the remaining Psammonemata, it 

 will be necessary to adopt a character if possible by which 

 the genus Spongelia may be distinguished. Hence as the 

 typical composition of the vertical or areniferous fibre in 

 Spongelia consists of foreign objects enveloped in a layer of 

 Jceratine which can hardly be seen with the naked eye, and in 

 all the 3pecies above it for the most part this layer is the 

 most predominant part of the fibre, it seems to me that this 

 character, which I grant is only one of degree, is the most 

 useful for the occasion that I can adopt. 



I have already alluded in the introductory part of this 

 communication to the general character of the fibre in Spon- 

 gelia, as evidenced by Schulze's representation of a fragment 

 of the skeleton of 8. pallescens (I. c), confirmed by a typical 

 specimen of the same species which came direct from Schmidt, 

 who established the genus; therefore I have only to extend 

 Schmidt's original diagnosis to meet our present requirements, 

 which will thus stand as follows : — 



Gen. SPONGELIA, Xardo ap. Schmidt. 

 Char, emend. Form massive, simple or lobed, sessile or 

 stipitate. Consistence soft and resilient when wet, firm when 

 dry. Colour violet when fresh, sponge-colour when dry. 

 Surface conulated in bold relief or entirely smooth. Pores 

 restricted to the dermal membrane, tympanizing the intervals 

 between the conuli or dispersed generally where there are 

 none. Vents on the prominent or projecting parts. Internal 

 structure loose, fibro-reticulate ; vertical fibre arenaceous, 

 lateral fibre chiefly keratose. 



Obs. If this diagnosis be followed, then Spongelia avara, 

 Sdt., according to Schulze's representation (op. et loc. cit. 

 Taf. vi. fig. 4) , and my own typical specimen, would not come 

 under it, but under that of Dysidea. I have not had an 

 opportunity of examining the other species of u 8pongeMa" 

 mentioned by Schmidt; but a typical specimen of the pre- 

 ceding genus, viz. Cacospongia cavernosa, indicates from its 

 hollow thin-walled fibre, together with other characters, that 

 it is an Aplysina rather than a Psammonematous sponge. 



There is only one specimen of Spongelia in Mr. Wilson's 

 collection, which may be named and described as follows : — 



Spongelia stellidermata, n. sp. 

 Specimen erect, thick, spatulate, compressed, stipitate, thin- 

 ning from the centre towards the upper margin and sides, which 



