Page:Popular Science Monthly Volume 3.djvu/552

536 envelop of lime, this had a core or axis of silica, and a bark of keratose. According to Dr. Gray, the Hyalonerna was really two animals, namely, the polyp, represented by the glass coil, and its horny crust; and the sponge, represented by the conical spicular mass, which as a new species he named Carteria.

Prof. Milne-Edwards, in 1857, described the sponge-mass and the glass-rope as but one animal, and "degraded the zoophyte to the rank of an incrusting parasite."

In 1859 appeared the magnificent work of Dr. Brandt, of St. Petersburg, on the Hyalonema. Now, the tables are completely turned. The silicious rope, and its warty bark, are declared to be parts of a polyp, and the sponge is announced as the parasite!—"attaching itself to the polyp, gradually penetrating its silicious axis, and finally killing it." Poor, innocent sponge! Even at the risk of being unparliamentary, we rise to brand that statement as a libel on the sponge.

In 1860 appeared the elaborate memoir on the Hyalonerna by Prof. Max Schultze, of Bonn. He describes the glass-coil and the sponge-mass as belonging to one and the same animal structure. The warty crust, or case, he refers to a distinct animal, a polyp to which he gives the name Palythoa fatua. Schultze, however, makes the polyp a "commensal" with the sponge; that is, they both live at the same table, which means that the sponge, by its ciliary action, has to supply food for both. Schultze's exposition is the generally accepted one. His idea of commensalism, however, the present writer cannot accept. Nor can he accept Milne-Edward's degradation of the zoophyte to a parasite. But want of room will not permit a statement here of the reasons of his disbelief.

The curious fact made clear is that, through all these years of earnest investigation, Hyalonerna was studied upside-down, until Prof. Lovén published his ingenious paper (in 1867, we think), in which, by a little stalked pyriform deep-sea sponge, he demonstrated the true position or attitude in life of the Hyalonerna. In 1870 Prof. Joseph Leidy attained the same conviction from a different line of argument. It was pretty much as if one should ask, "Should a house stand on its chimney?" Says Dr. Leidy: "It has occurred to me that the sponge-mass, in its natural position, was uppermost, and was moored by its glassy cable to the sea-bottom; this opinion is founded on the circumstance that in sponges generally the large oscules from which flow the currents of effete water are uppermost." In fact, these glassy threads, at their lower extremities, spread out in a spiral manner, much like the spray from a turbine water-wheel, and, thus penetrating the mud, afford a good anchorage. This mooring is greatly helped, too, by the peculiar structure of these long silicious needles. These needles, or glassy threads, are, in the body of the fascicle, or skein, cylindrical, and smooth; but, toward their extremities, they are