1138 A MONOGRAPH OF THE AUSTRALIAN SPONGES, 



a naked Osculum has the shape of a cylinder or cone and is some- 

 times compressed leaf-shaped measuring 10 — 30 x 5 — 30 mm. 

 It is attached by a broad basis or a rudimentary solid peduncle 

 is developed. The Osculum at the terminal end is circular or 

 oval and measures 3 — 10 mm., in diameter. Sometimes it is 

 closed. The colonial form without Oscula appears as a large 

 undulating mass with highly projecting gyri and often represents 

 a "range of volcanoes" (Haeckel (1). The largest Sponge seen 

 by Haeckel measured 60 x 40 mm. Carter (2) was therefore 

 wrong to say, that his Teichonella prolifera is " by far the largest 

 Calcisponge on record " I have seen specimens measuring 140 x 

 80 x 30 mm., which were only fragments brought up by the 

 dredge, so that the upper limit in size to which this Sponge may 

 grow, is unknown. 



The canal system. 



The body wall is from 2 to 5 mm. thick, the Gastral cavity 

 follows in shape the outer surface pretty regularly, but is not 

 influenced by the external Gyri, the body wall is very much 

 thicker 5 mm. The canal system is simple. The outer cortex is 

 perforated by numerous small pores, which are equi- distant, and 

 measure 04 mm. in diameter, the solid parts of the cortex 

 between them are of the same dimensions as the pores. Below 

 the pores the inhalent canals commence wich trumpet shaped 

 extensions, and lead centripetally downwards into the Parenehj'ma. 

 These canals are cylindrical and situated radially, they measure 

 - 16 mm. in diameter and do not taper towards their centripetal 

 termination, but end cul-de-sac like. No tangental inhalent 

 canals are met with ; there exists no anastomosis or sub-dermal 

 cavities. The ciliated chambers measure 04 mm. across. The 

 exbalent canal system is slightly more complicated. 



Eadial canals, parallel to the inhalent ones, lie between the 

 latter and have the same shape and dimensions as these. They do 



(1.) K Haeckel. Die Kalkschwamme. Eine Monographic Band II., 

 Seite 229. 



(2. ) //. T. Carter. On Tcichonia, a new Family of Calcareous Sponges, 

 with descriptions of two species. Annals and Magazine of Natural History 

 5th series. Vol. II., Nr. 7, p. 37. 



