Page:Popular Science Monthly Volume 3.djvu/559

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THE GLASS-SPONGES.
543

gether. From the sponge of the toilet this sarcode and its spicules have been all removed. The interesting fact is that, while these spicules are arranged in different patterns, many being made to radiate like stars, no two species have the same pattern. Look at Fig. 6, which represents the spicules of Pheronema. It looks as if

Fig. 7.

Section of the Outer Wall of Ventriculites Simplex, showing the structure of the silicious network. Magnified 50 times.

the series were united together to make an irregular star. Now, one of these needles sticks perpendicularly into the sarcode, leaving the other rays to spread out in a plane, to which the one that serves as a spike is perpendicular. One might liken it to a parasol without its silk covering—the handle in the hand is the spike, and the steel ribs

Fig. 8.

Extremity of a Mooring-thread of Pheronema, showing the notched sides and the anchor-flukes at the end. Greatly magnified.

spread out will represent the silicious rays, or spicules. At a little distance from this penetrating needle, or spike, the needle of another of these irregular stars pierces the sarcode. Of consequence, the radiating needles, or spicules, of each one of these irregular stars lock into the similar spicules of the adjoining star, and so on for the entire mass, until it has the effect of felt; with this great difference, however—so regular is this natural felting of the sponge-flesh—that the whole mass is spiculated or laid out in quite regular and pretty patterns; and such is the uniformity of pattern for each kind that they actually