Page:Natural History, Mollusca.djvu/144

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132
TECTIBRANCHIATA.—PLEUROBRANCHIDÆ.


and the edges of the mantle being incurved on all sides around the foot—may have in some measure prevented the access of the water to the vital parts. At the end of that time I replaced it in sea-water, where it soon partially recovered its activity, relaxed its mantle, and contracted it dorsally so as to expose the groove between it and the foot, greatly protruding the tentacles and veil, and the branchial plume; thus I was enabled to get a much better sight of these parts. As soon as it was replaced in the sea-water, a quantity of white mucus was discharged from the whole surface, most copiously from the foot, which as it lay on its back was uppermost. This mucus gradually, by the contractions of the animal, was accumulated in a knob at the posterior end of the foot, and then thrown off. The reticulate structure of the mantle integument was much more distinct than in health; it was seen to form a delicate lacework of yellow fibres all over the surface, covering and enclosing a pellucid parenchyma.

The animal evidently had been injured by its bath of fresh water; for it lay on its back, expanding and contracting its various parts, without the power of turning over to crawl, or even of adhering by the foot when turned, but rolling helplessly back. The form and appearance, too, were very different from those of health; the groove being widely exposed by the contraction of the mantle, in which state the animal resembled some published representations of it more closely than when in health.

The student of nature, one who really delights to contemplate the wonderful works of God, as they appear in the conditions and under the circum-