Introductory report on the natural history of the pearl oyster of Ceylon.

  • Kelaart, E. F. (Edward Frederick), 1819-1860.
Date:
[1857]
Catalogue details

Licence: Public Domain Mark

Credit: Introductory report on the natural history of the pearl oyster of Ceylon. 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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    Conchologists have long agreed, that Lamarck was right in separating the Pearl Oyster, par excellence, from the old genus Avicula, of wliich there are several species in Ceylon, some producing valueless pearls of a dusky blue and blackish colour. The only description of the Pearl Oyster of Ceylon I have access to, is Lamarck's, in his Hisiuire Naturelle sans Verfebres, and that, too, is only of the shell. Meleagrina testa, subquadratd, superne rotundatd, fusco vi- rente. Alho radiata, lamellis per series longitudinalis imhricatis, supeiioribus majorihus.—Lamarck, vol. 7, p. 107. 6. . The Ceylon shell is a variety of that above described. The white radiating lines are alternated with rays of a red or black colour. Doctor Templeton made it appear, that the Ceylon variety corresponded with Leach's description of his Avicula radiata. I am more inclined to believe, that they are only accidental or occasional varieties. The shell, how- ever, appears to attain a larger size in America, and in the Persian Gulph, than in the Seas of Ceylon. In the largest Ceylon shells, the red or black radiating lines become obsolete. If they are permanent varieties, they are both found in Cey- lon. I have a faint recollection of having seen both varieties on the Pearl banks of Arripo. I had also a small perfectly wliite Pearl Oyster; this may be an Albino specimen, or La- marck's Meleagrina albina. 31. testa albidd, irradiatd, obsolete squamosa ; auriculas duabus semper distinctis, originally found on the coasts of New Holland and Van Diemen's Land. On removing the animal from the shell, the whole of the internal parts is seen enveloped in a membrano-muscular covering, called the mantle, and known popularly in Ceylon as the sAm. The free border of the mantle lining each valve, dips downwards, to meet a similar veil on the opposite side ; thus forming a kind of double fringed veil. Tlie one set of tentacular fringe, in immediate contact witli the shell, is composed of hairy tentacles, looking horizontally forwards