Sponges front South Australia. 205 



conular elevations of the subjacent tissue, with an indistinct 

 reticulation between them ; fibrillse of the dermis colourless, 

 plentifully accompanied by minute dark pigmental cells. 

 Pores in the interstices of the dermal reticulation now (pro- 

 bably from contraction) only discernible under the microscope. 

 Vents scattered over the surface, but small, probably from the 

 same cause. Parenchyma chiefly composed of fibrillose sar- 

 code structurally blended with the fibrillse of the dermis, but, 

 from the comparative absence of pigmental cells, much lighter 

 in colour ; charged more or less with grains of sand and other 

 foreign microscopic objects, which, in some parts, are sur- 

 rounded by layers of amber-coloured keratine, so as to form 

 unconnected and ill-defined short fragments or traces of 

 genuine fibre, which is otherwise absent. Size of specimen 

 2 in. high by 4x 2 in. horizontally at the base. 



Hab. Marine. 



Loc. Port Phillip Heads, South Australia. Depth 19 fath. 



Obs. The dark purple colour of the surface with the sub- 

 cellular elevations, together with the fragmentary character of 

 genuine fibre produced here and there by the development of 

 keratine lamina? round some of the foreign objects of the 

 interior, appear to me to ally this remarkable sponge to the 

 third family of the Ceratina more than to any other group ; 

 while its intense wood-like hardness and the fact that, when 

 cut into, the interior is yellow, but rapidly changes before the 

 eye to green and lastly lead-colour or grey, after the manner 

 of the poisonous Boletus, viz. B. luridus, are peculiarities 

 which cannot fail to point out the species. 



Moreover, I now find, from having such a well-preserved 

 and large specimen to deal with, that the small dried frag- 

 ment from Australia that I described and represented with 

 the Trincomalee species under the name of Aplysina purpurea 

 ( l Annals,' 1881, vol. viii. pp. 103, 104, pi. ix. fig. 2, a, b, c), 

 should not have been included under this name, but, being- 

 identical with that in Mr. Wilson's collection, should, on the 

 contrary, be considered as a specimen of Pseudoceratina 

 durissima. 



Pseudoceratina crateriforviis (provisional) . 



Massive, sessile, wide, conical, wrinkle-ridged, truncated 

 at the summit by the opening of a large cloacal crateriform 

 vent. Consistence resilient. Colour, when fresh, " greenish 

 grey j" the same now. Surface deeply wrinkled with high 

 ridges more or less interunited by ramification ; the whole 

 covered with a sandy incrustation in the form of a minutely 

 reticulated or sieve-like structure, whose interstices are tym- 



Ann. ti; Matj. N. Hist. Ser. 5. Vol. xv. J 5 



