Observations on the generation of the lobularia digitata / by R. E. Grant.

Date:
[1828?]
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the generation of the lobularia digitata / by R. 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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    differing much from those I had already examined. Both the red and white varieties of this animal of various shades of in- tensity, are found in every part of the Frith of Forth from this to the opposite shore, adhering in large masses to stones, shells, and fuci. At low water we observe it hanging in nu- merous fleshy lobes from the under and sheltered surface of rocks; after storms, quantities of it are often left on shore, adhering to marine plants and animals which have been torn from their seat; and by accompanying the dredgers daily em- ployed in the Forth we constantly find it brought up by the dredges from deep water, spreading on all kinds of solid sub- stances lying at the bottom, as broken bottles, glasses, shells, &c. Jussieu examined the structure of this animal with the mi- croscope, on the coast of Normandy, more than eighty years ago, and has given accurate representations of many parts of its structure (Mem. deVAc. 1742.^. Mr Ellis, who mentions it as occurring in great plenty round all the coasts of the Bri- tish islands, has given many excellent figures illustrating its internal structure, the appearance and situation of its ova, and their mode of passing out through the bodies of the polypi (Phil. Trans, liii. PI. XX.^. He has placed groups of 5 — 8 loose ova in each of the canals below the polypi, and similar groups in the transparent bodies of the polypi below the stomach, which are represented passing up one after another towards the mouth. It is to be regi'etted that he has not left a full description of the interesting appearances represented in these figures. Dr Spix of Bavaria, without noticing the accurate and elegant plates of Mr Ellis, and with a low esti- mation of the labours of our distinguished countryman, has given several figures to illustrate the mode of generation of the Lobularia (Ann. du Mus. t. xiii. PI. XXXIII.^, which differ as much from nature as they do from the plates of his prede- cessor. He has represented the head of the polypus as con- sisting of a large round vesicle or stomach, to the sides of which are closely applied eight thick cylindrical claviform ten- tacula covered with minute papillae; descending from the stomach he has represented a long narrow tapering tube, and the ova are placed in a single line, inclosed in a small curved canal, like a string of beads. His observations correspond