of the glass-sponges is the emphatically deep water. There are precious stores of exquisite forms and structures, that have never been seen by any except their Creator. One of these, described in Dr. Thompson's book, which was obtained during the cruise of the Lightning, is named in honor of M. Holten, the Danish governor at Faroe, and Prof. Carpenter—hence the appellation Holtenia Carpenteri. It is about nine inches long, and three and a half inches wide. The body of this glass-sponge is of an oval, or egg-shaped form. At the bottom is a great mass of fine silicious threads, like white hairs, wadded together like a mop. These are its anchoring threads. There is a crater, or oscular opening at top, about three-fourths of an inch wide, around which, on the outside, short threads of silica stand out, not unlike a beard. Thus the upper part of the sponge might be likened to a bird's-nest. Hence the Setubal deep-sea shark-fishers, who sometimes bring them up from great depths with threads of Hyalonema on their fishing-lines, call them "sea-nests." The spicules are arranged in little stellate groups, the effect being that the entire surface of the sponge has an ornamentation of stars.
We can mention but one more of these singular beings. This is the Rossella velata, Fig. 5. And here we will borrow Dr. Thompson's own words: "On August 30, 1870, Mr. Gwyn Jeffreys dredged in 651 fathoms in the Atlantic off the mouth of the strait of Gibraltar an exquisite sponge, resembling Holtenia in its general appearance, but differing from it in the singular and beautiful character of having a delicate outer veil, about a centimetre from the surface of the sponge, formed by the interlacing of the four secondary rays of large five-rayed spicules, which send their long shafts from that point vertically into the sponge-body. The surface of the sponge is formed of a network of large five-radiate spicules, arranged very much as in Holtenia; but the spicules of the sarcode—the small spicules which are embedded in the living sponge-jelly—are of totally different form. A single large 'osculum' opens, as in Holtenia, at the top of the sponge, but instead of forming a cup uniformly lined with a netted membrane, the oscular cavity divides at the bottom into a number of branching passages, as in Pheronema Annæ, described by Dr. Leidy. The spicules of the 'beard' are more rigid and thicker than those of Holtenia, and scattered among them are some very large four-barbed grappling-hooks." Such is the capital description of the learned naturalist. To be sure, some old "salt" would be more laconic; for he doubtless would tell you that it was like a pine-apple, with the crown and its core removed.
We have tried to make plain what is meant by sponge-flesh, for which the word sarcode is used. It should be understood that this sarcode, which is a semi-fluid substance, is simply held to the mesh-like skeleton and to itself by the interlacing of tiny needles of flint, called spicules, so that the albuminous-like flesh is really felted to-
