Dysidea chaliniformis

Hab. Marine.

Caulescent, branched, stipitatc; consisting of a compressed bunch of solid cylindrical stalks rising from a common stem; branches numerous, small and simple below, some not more than ⅛ in. in thickness, ending in a sharp point, which is sometimes bifurcated; increasing in size upwards, dividing and interuniting; the whole most irregularly. Consistence light, fragile, compressible. Colour reddish brown. Surface even, but minutely wrinkled from the sinking of the dermal pore-membrane upon the subjacent arenated fibre. Pores plentifully scattered throughout the dermal membrane. Vents also numerous, scattered over the flattened portions of the branches or in a line along them. Structure fibrous, fibre arenated throughout; texture fine. Size of specimen about 12 in. long by 5 x 1 in. horizontally. Great diversity in the size of the branches, of which the largest and longest are ¼ in. in diameter, while the smallest do not exceed yof an inch.

Obs. The caulescent character of this species, together with the solid, cylindrical, simple, and subdivided condition of the branches and the arrangement of their vents, would, at first sight, lead to the supposition that it was a specimen of Chalina polijehotoma, Esper, = Chalina oenlata, Bk., such is the tendency, as before stated, of the sponge-sarcode throughout the class to produce the same kind of forms whatever the composition may be; so that here, although the form is like that of a caulescent Chalina, the characteristic toughness and resiliency of the latter, which arises from the presence of a large amount of keratine, is absent in Dysidea, chaliniformis, where the opposite state renders it so brittle that, when wet, it is almost impossible to handle the specimen without a piece coming off, and in drying it breaks down under the slightest force. There is another chaliniform specimen in the collection, but here the increased development of keratine, of which the lateral fibre is exclusively composed, not only lessens the amount of brittleness, but necessitates its being relegated to another genus, in which it will be found hereafter.

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