Sponges from South Australia. 285 



in all stages of development, viz. from that of simple approxi- 

 mation, followed by a covering composed of several layers of 

 kerasine, to that which afterwards became sirailarlj extended 

 into the usual laminated Hlament. So that it may fairly be 

 assumed that the lirst-formed tibres of the skeletal structures 

 throughout originated in this way, viz. from the "horn-cells " 

 attached to the object on which the specimen grew. Size of 

 specimen about 3 in. high by 3 x 2 in. horizontally. 



Loc. Port Western. 



Obs. There is another specimen of this kind in which the 

 skeleton appears to be more reticulate but formed after the 

 same plan, viz. by " horu-cells " applied to the exterior of the 

 main filaments, and, indeed, so might the skeletal fibres of 

 Dendrilla rosea at the commencement, although gathered 

 together afterwards spirally from the root-like expansion into 

 a common trunk ; but they do not do so above this, for in the 

 divisions of the hranchletSj when placed under the microscope, 

 the latter may be seen to arise from a budding-off of the central 

 canal, although the subsequent thickness of the fibre appears 

 to be added by layers of kerasine applied to the exterior, that 

 is by the sarcode, as in Aplysiaa massa. 



In Aplysina massa too the same kind of large nucleated 

 epithelial cells of the surface, averaging 5-6000ths in. in 

 diameter, are to be found as in Dendrilla rosea &c., but 

 accompanied by much smaller granuliferous ones, about 2- 

 6000 ths in. in diameter, that appear to be endogenously 

 derived from them, and which, in the blood-red species about 

 to be described, viz. Ajjlysina cruorjSire seen to be the pigment- 

 cells or bearers of the red colouring-matter of this species, all 

 of which Jimt present themselves as coloured granules in the 

 large epithelial cells. 



Lastly, the fibre of this species is also traversed by a para- 

 site in the form of a branched fungus, which gives it the 

 appearance of Bowerbank's imaginary genus Auliskia. The 

 filaments, too, of this organism are often fructiferous. 



Aplysina noivus, Carter. 



Aphjsina navus, Carter, ' Anuals,' 1870, vol. xviii. p. 229, pi. xii. figs. 1 c 

 and 2. 



Growing over both valves of a large mussel in an incrusting 

 form. Consistence soft. Colour, when fresh, "coffee-brown." 

 Surface presenting the usual soft fibro-reticulated structure, 

 here charged with a few fine, foreign, acerate spicules and 

 supported on the ends of short, skeletal, keratose filaments, 

 arranged vertically, so as to raise the reticulated structure 



