This is only one of the ways by which sponges anchor themselves in the ooze of the deep sea. Hyalonema sends right down through the soft mud a coiled wisp of strong spicules, each as thick as a knitting needle, which open out into a brush as the bed gets firmer, and fix the sponge in its place somewhat on the principle of a screw pile. A very singular sponge from deep water off the Lofoten Islands spreads into a thin circular cake, and adds to its surface by sending out a flat border of silky spicules, like a fringe of white floss round a little yellow mat; and the lovely Euplectella, whose beauty is imbedded up to its fretted lid in the gray mud of the seas of the Philippines, is supported by a frill of spicules standing up round it like Queen Elizabeth’s ruff. The sponges of the deep-water ooze are by no means confined to one group. The Hexactinellidæ are perhaps the most abundant, but corticate sponges even, closely allied to those which look so rigid when fixed to stones in shallow water, send out long anchoring spicules and balance themselves in the soft mud; and off the coast of Portugal Mr. Gwyn Jeffreys dredged in 1870 several small forms of the Halichondridæ, with long supporting fibrous beards. From its appearance when brought up Holtenia evidently lives buried in the mud to its upper fringe of spicules. When freshly dredged, it is loaded with pale gray semi-fluid sarcode, full of Globigerinæ, Triloculinæ, and other rhizopods, and covered in our northern localities with the little ophiurid Amphiura abyssicola, Sars, and the exquisitely delicate transparent clam, Pecten viterus Chemnitz. Holtenia extends from the Butt of Lewis to Gibraltar, in from 500 to 1,000 fathoms. In the Hexactinellidæ all the spicules, so far as we know, are formed on the hexradiate plan; that is to say, there is a primary axis, which may be long or short, and at one point four secondary rays cross this central shaft at right angles. In many of the Hexactinellidæ the spicules are all distinct, and combined, as in Holtenia, by a small quantity of nearly transparent sarcode; but in others, as in “Venus’s flower-basket,” and the nearly equally beautiful genera Iphiteon, Aphrocallistes, and Farrea, the spicules run together and make a continuous silicious network. When this is the case the sponge may be boiled in nitric acid, and all the organic matter and other impurities thus removed, when the skeleton comes out a lovely lacy structure of the clearest glass. The six-rayed form of the spicules gives the network which is the result of their fusion great flexibility of design, with a characteristic tendency, however, to square meshes. Off the Butt of Lewis, in water of 450 to 500 fathoms, we met on two occasions with full-grown specimens of a species of the remarkable genus Hyalonema, with the coils in the larger examples upward of 40 centimetres in length.