Sponges from South Australia. 509 



tripodifera, but the tubulation, instead of being echinated 

 and closed in, is without echination and separate ; still, oxir 

 " intervals," which in C. tripodifera we have considered to 

 be analogous to Hackel's " Intercanal System," are here 

 simply open vacuities. Not considering these differences 

 sufficient to constitute a distinct species, it has been desig- 

 nated as a variety of G. tripodifera. 



Hitherto the structure has not presented any indications of 

 that cancellous kind which we have called " ])arenchyma," 

 although there has been a more or less distinct cloaca and 

 general vent, especially in Clathrina triiJodifera, that is there 

 is no additional structure of this kind to be seen outside or 

 inside the wall of the tubulation; but now. we come to a 

 structure in which there is a faint trace of this parenchyma in 

 the angles of union of the lamina of which it is composed, as 

 will be described in the following species. 



5. Clathrina laminoclathrata (dry). 



Specimen a subcircular patch about | in. in diameter 

 and -^ in. thick, which has grown over a rocky substance. 

 Clathrous, massive, sessile, spreading, lamino-reticulate. Colour 

 now (that is in its dry state) steel-grey. Surface even, smootli, 

 reticulated by the clathrous holing of the structure generally, 

 which here makes its appearance in the form of circular inter- 

 stices of different sizes up to -jj in. in diameter. Pores in the 

 lamina. No appearance of a vent or vents of any kind, i. e. 

 spurious or real. Structure lamino-clathrous ; lamina sqjid, 

 composed of a thin layer of radiate spicules supporting the 

 sarcode and other soft parts. Spicules of one form only, viz. 

 triradiate, equiarmed and equiangled, varying in size under 

 75-6000ths in. in diameter, ray alone about 45 by o-6000ths in. 

 Size above given. 



Ohs. In this instance, which is unique among the calca- 

 reous sponges so far as I know, the tubulated staple thread 

 of Clathrina^ which so generally characterizes this genus, is 

 replaced by a flat, solid, " tape-like " form or staple, whose edge 

 when cut presents no appearance of mesodermal structure or 

 parenchyma whatever, although towards the angles of union, 

 where of course the lamina branches off to form the clath- 

 rous structure of the mass, there is a small angular space left 

 which bears a faint trace of parenchyma, and this seems to 

 introduce us to what in this way will become so much more 

 evident hereafter. It is represented among the non-calcareous 

 sponges by ^' Echinoclathria favus^^ ('Annals,' 1885, vol. xvi. 

 p. 292). 



