The anatomy and physiology of the perforating instruments of Pholas dactylus : being notes read before the Brighton and Sussex Natural History Society, on the 11th November, 1858, and 10th February, 1859 / by John Robertson.

  • John Robertson
Date:
1859
Catalogue details

Licence: Public Domain Mark

Credit: The anatomy and physiology of the perforating instruments of Pholas dactylus : being notes read before the Brighton and Sussex Natural History Society, on the 11th November, 1858, and 10th February, 1859 / by John Robertson. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    NOTES. [note I.] Brighton, 1st June, 1851. Having, while residing here, opportunities of studying the Pholas Dactylus, I have endeavoured during the last six months, to discover how this mollusc makes its hole or crypt in the chalk ; by a chemical solvent ? by absorption ? by ciliary cur- rents ? or by rotatory motion ? My observations, dissections, and experiments, set at rest all controversy in my own mind. Between twenty and thirty of these creatures have been at work in lumps of chalk in sea water in a finger glass and a pan, at my window, for the last three months. The Pholas Dactylus makes its hole by grating the chalk by its rasp-like valves, licking it up when pulverised, with its foot, forcing it up through its principal or branchial siphon, and squirting it out in oblong nodules. The crypt protects the Pholas from conferve, which, when they get at it, grow not merely outside, but even within the lips of the valves, prevent- ing the action of the siphons. In the foot there is a gelatinous spring or style, which even when taken out has great elasticity, and which seems the main- spring of the motions of the Pholas Dactylus. [.NOTE II.] Mr. J. Kobertson wrote to say that the ideas emitted re- cently by M. Cailliaud upon the perforations of rocks by the Pholades, had been published by him previously, especially in a letter of June last, in the New Edinburgh Magazine, the Naturalist, the Zoologist, and he added that in August last he arrived in Paris with his Pholades still living, and that he had shown their stone to different persons, among others M Valen- ciennes. Mr. John Robertson has offered his assistance to the authorities of the Jardin des Plantes of Paris, and the Zoologi- cal Gardens of London, to make a permanent exhibition of per-