Page:Popular Science Monthly Volume 10.djvu/278

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264
THE POPULAR SCIENCE MONTHLY.

In Fig. 3 we have an enlarged restoration, after Dawson, of a portion of the Eozoön structure, which will enable us to better appreciate the several parts of the organism. The dark, granulated layers at the base and at intervals higher up constitute the chambers, and contain the sarcode or gelatinous animal matter. Immediately above and below each dark layer is the thin calcareous shell penetrated by the minute orifices or tubuli. The white spaces represent the supplementary skeletons traversed by the larger canals. At the summit the sarcode is developed into several pseudopodia or cilia, by means of which food is brought to be assimilated.

PSM V10 D278 Eozoon restored.jpg
Fig. 3.—Eozoön restored. (After Dawson.)

In Fig. 4 we have a portion of Eozoön magnified one hundred diameters, drawn by Carpenter. The upper covering (a a) represents the original cell-wall penetrated by the tubuli or pores in great abundance. A bit of this is still more magnified in 2, by the side of the first, seemingly consisting of an upper and lower part. The greater part of the sketch consists of the supplemental or intermediate skeleton, traversed by two kinds of canals (b, c), of much larger size and greater irregularity than the tubulation of the cell-wall.

The arrangement and composition of the mineral matter of the Eozoön is quite interesting, and the more remarkable since it has