Observations on the spontaneous motions of the ova of the campanuloria dichotoma, gorgonia verrucosa, caryophyllea calycularis, spongia panicea, sp. papillaris, cristata, tomentosa, and plumularia falcata / by Robert E. Grant.

Date:
[1826]
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the spontaneous motions of the ova of the campanuloria dichotoma, gorgonia verrucosa, caryophyllea calycularis, spongia panicea, sp. papillaris, cristata, tomentosa, and plumularia falcata / by Robert E. Grant. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    Mr Ellis, though not altogether correct in its detail, is satisfac- tory as to the motions of the ova which he saw escape from the vesicles. As this species of Campanularia occurs abundantly on Leith rocks, and, at this time (May) presents the ova in a state of maturity, I have examined their singular motions under the microscope, in presence of some friends conversant with the structure of these animals. The moving ova which Mr Ellis observed, were not, as he supposed, the same with the polypi- like bodies he has represented (PI. xxxviii. Fig. 3. 13, B, B,) hanging from the mouths of the vesicles, but were ova which had fallen from these polypi-like bodies. The polypi-like bo- dies, viewed under the microscope, are found to be thin, trans- parent, motionless capsules, containing each three distinct ova, and presenting at their free extremities several stiff, straight, di- verging pointed processes, which Mr Ellis mistook for the ten- taeula of a young polypus; and was thus led to believe, that the polypus is the first formed part of a young zoophyte, which I have found by experiment to be contrary to fact. This mode of generation in Sertularia, by the detachment of numerous capsules, containing ova enveloped in a viscid matter, was known to Cavolini, who, forty years ago, detected the fallacy of Mr Ellis’s statement regarding the polypi-like bodies, and suspected that the true ova contained in these exterior capsules, would be found to exhibit the same kind of motions which he had ob- served in the ova of other zoophytes; but he did not succeed in obtaining the ova after their expulsion from the capsules, so as to verify or refute his conjecture. As I had already observed through the transparent vesicles of the Plumularia falcata the motions, and even the ciliae, of the ova contained in them, I placed one of the polypi-like capsules hanging by umbilical cords, from the vesicles of the Camp, dichotoma entire under the microscope, and I could distinctly perceive the vortex-like cur- rents along the surface of the contained ova, and that particu- lar vibrating zone immediately around them, which we always observe along a ciliated surface, when the ciliae are in too rapid motion to be distinctly seen. On allowing the three ova to es- cape into the water of the watch-glass, by tearing open the cap- sule with two needles, they immediately began to glide to and fro along the bottom, and I could now perceive the ciliae vibrat-