. Evenings at the microscope : or, Researches among the minuter organs and forms of animal life . Zoology; Microscopy; Microscopes. SEA-UEOHINS AND SEA-CUCUMBEBS. 281 open space left between these projecting radii is filled with the solid glassy matter, having, as we see, a convex sur- face. This, however, from its perfect transparency, is not seen when we look at the side of the spine, the eye going down through the transparent matter to the bottom of the space. The spine is, in fact, a fluted column of spongy glass, with the grooves filled with solid glass. We have not yet seen, however, the
. Evenings at the microscope : or, Researches among the minuter organs and forms of animal life . Zoology; Microscopy; Microscopes. SEA-UEOHINS AND SEA-CUCUMBEBS. 281 open space left between these projecting radii is filled with the solid glassy matter, having, as we see, a convex sur- face. This, however, from its perfect transparency, is not seen when we look at the side of the spine, the eye going down through the transparent matter to the bottom of the space. The spine is, in fact, a fluted column of spongy glass, with the grooves filled with solid glass. We have not yet seen, however, the beautiful mechanism appropriated to the movement of these spines. You can hardly see this to advantage in the living animal, but here is the entire shelly box of a dead Echinus, on which, while for the most part the surface is denuded of spines, a few dozen remain sufficiently attached to show what I wish to demon- strate, viz., the mode of articu- lation. You observe that the whole globose shell is covered with tiny knobs, differing in size, and not set in very re- gular, or at least not very ob- vious, order, but showing a tendency to run in lines from pole to pole of the globe. Giving attention to one of the larger of these knobs, under a lens it is seen to be. a hemi- spherical eminence on the shell, the very summit of which is crowned by a tiny nipple of polished whiteness, resem- bling ivory. Now if we carefully lift one of the still remaining spines from its attachment, which in its present dried state is so fragile that the slightest touch is sufficient for the purpose, we shall note that its base rests on this tiny nipple ; and on turning it up, and bringing the mag- nifying power to bear upon its base, we see that this is excavated with a hollow, whose dimensions exactly corre-. 8PINE of echinus. Segment of Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance o
Size: 1264px × 1976px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookce, bookdecade1870, booksubjectmicroscopy, booksubjectzoology
