120 Mr. H. J. Carter on the 



the ova developed in the intercameral tissue (fig. 7, n } o) to 

 pass into the chamber and thus be expelled. Therefore these 

 holes would seem to have more functions than those ascribed 

 to them in the wall of the ampullaceous sac of the so-called 

 "siliceous sponges," ex. gr. Spongelia avara (Schulze, I. c). 



Returning to the latter then I find two undescribed species 

 of my order Psammonemata among Mr. Wilson's dreclgings, 

 in which what I have above stated respecting the mode of 

 circulation is particularly well illustrated, not only on account 

 of the fact itself, but on account of its being present in two 

 totally different structures. These species, which I have 

 respectively named Geelongia vasiformis and Hircinia solida, 

 will be more particularly described in another paper for 

 future publication, but may here, for convenience, be briefly 

 noticed as follows : — 



Geelongia vasiformis. 



Vasiform, stipitate, 6| inches high by 6 inches across the 

 brim, diminishing to the stem, which is 2\ inches long and 

 1^ inch in diameter, ending in a root-like expansion ; with a 

 thickness of wall at the bottom amounting to 5-8ths inch, 

 diminishing gradually to the brim, which is even and round ; 

 covered externally by a thick dermal layer of sarcode charged 

 with sand, in which are the pores and a few small scattered 

 vents ; and internally, with a layer of the same kind, in which 

 there are larger vents alone, that is with no pores, which are 

 numerous and, in one specimen, uniformly spread over the 

 upper half only of this surface, the lower part being entirely 

 smooth. No conuli on either side. 



Hircinia inter texta. 



Compressed, oblong, flat, sessile, 12 inches high by 6 inches 

 wide, with irregularly undulating, rounded margin on all 

 sides, and a thickness of \\ inch below, which diminishes to 

 about | inch in the upper part ; covered on both sides with a 

 soft, reticulated, dermal layer of sarcode without foreign bodies, 

 in the interstices of which the pores are situated, the whole 

 being thrown up into obtuse conuli or monticular elevations, 

 in bold relief, by the projection of the subjacent keratose fibre ; 

 and the vents, which are small and scantily scattered over 

 both sides, are largest and most numerous on the upper border. 

 Conuli on both sides. 



With these two distinct forms come two distinct arrange- 

 ments of the internal structure — that is, in Geelongia vasiformis 



