Sponges from South Australia. 39 



iiead, which altogether is only H inch in its shortest diameter, 

 while its longest, as above stated, is 3 inches, another character 

 of Grantia comjyressa and its varieties. 



The crater- or basin-like form, together with the arrange- 

 ment of the excretory canal-system, causes this sponge 

 to be very analogous in these respects to Carteriospongia, 

 Hyatt, among the Keratosa, wherein the openings of the 

 latter on each side of the wall being opposite each other, 

 causes the specimen to present a cribriform appearance when 

 placed between the observer and the light. 



Observation. 

 We have now to leave that portion of Mr. Wilson's collec- 

 tion in which the typical form of the " radial chamber," viz. 

 that in Grantia ciliata^ which consists of an unbroken cylinder 

 extending directly across the wall from the cortex to the 

 cloaca, is replaced by a 5MZ»radial structure, in which the 

 typical radial parallelism is more or less lost by the addition 

 of large holes of intercommunication, more or less equal in 

 diameter to the chambers themselves, which thus introduces 

 a branching structure that is better seen in the vertical 

 or horizontal section of the specimen than in the tangential 

 one of the wall, in which the ends of the chambers appear to be 

 almost as regular and as much in juxtaposition as they would 

 be in Grantia ciliata. Hence the calcareous sponges pre- 

 senting this " subradial " structure will be generically termed 

 '•'■ Hypograntia " under the following diagnosis : — 



Hypograntia. 



Calcareous sponges in which the typical or radial structure of 

 Grantia ciliata is more or less diverted from its parallelism by 

 the addition of large holes of intercommunication between the 

 chambers. 



15. Hypograntia infrequens (incertse sedis). 

 Individualized. Pyriform, sac-shaped, bent upon itself, 

 peristomed. Colour whitish yellow outside, ferruginous 

 within. Surface even, uniformly composed of large trira- 

 diates, fixed in their position by sarcode charged with minute 

 mortar-spicules. Pores in the structure last mentioned. 

 Vent single, terminal, circular, surrounded by the peristome, 

 leading into a narrow cylindrical cloaca, corresponding in 

 shape with that of the specimen ; holes in the cloaca small, 

 tolerably regular both in size and approximation, each pro- 

 vided with a sarcodic sphincter, like those of Grantia Giliata ; 



