Contributions to our Knowledge of the Spongida. 309 
more convenient opportunity of publication, from which the 
following species have been advisedly selected. 
Order III. PSAMMONEMATA. 
Family 1. BIBULIDA. 
Char. ‘ Solid fibre chiefly without core of foreign objects” 
i) J 
(‘ Annals,’ 1875, vol. xvi. p. 132). 
Coscinoderma lanuginosum, n. gen. et sp. 
Battledore-shaped, subsquare, compressed, stipitate, covered 
with a white, continuous cribriform incrustation of remarkable 
uniformity in its foramination. Surface for the most part even 
throughout, interrupted only by a small proliferous projection 
or outgrowth on one side and a line of vents situated pandean- 
pipe-like along the upper border, between which the structure 
is denticulated. Pores in plurality, situated in the sarcode 
tympanizing the interstices of the cribriform incrustation. 
Incrustation composed of microscopic foreign bodies, chiefly 
quartz-grains and fragments of sponge-spicules, imbedded in 
the anastomosing dermal fibre with such firmness, evenness, 
and regularity as to constitute a white, compact, reticulated, 
smooth, shagreen-like structure, whose interstices are uni- 
formly subcircular and about the same size, viz. 1-90th inch 
in diameter, underneath which again the “ subdermal cavities ”’ 
make their appearance in much the same form, but twice the 
size and in the midst of fibre only. Fibre not less remarkable 
than the incrustation, for there appears to be almost an entire 
absence of the usual attenuation, the whole being almost uni- 
formly alike in size and colour, viz. very small and fine, very 
long, scantily branched, curled up together in little whorls 
(representing so much wool under the same condition), of a 
deep sponge-colour, in the midst of which are excavated the 
channels of the pore and excretory systems, encircled respec- 
tively by the whorls of fibre, through which, in the absence 
of sarcode, their calibre is still maintained. When viewed 
under the microscope very few of the filaments are found to 
contain foreign bodies. Size of entire specimen 8 X 8 inches 
square by 14 inch thick; stem 2 inches long, 13 broad, 
and 4 thick, compressed, and terminated by a root-like ex- 
pansion. 
Hab. Marine. 
Loc. Freemantle, 8.W. Australia. 
Obs. The remarkable appearance of the incrustation, inter- 
nal structure, and characters of the fibre, if not the battledore- 
