On variation in the radulae of certain Buccinidae / by M.V. Lebour.

  • Lebour, Marie Victoria, 1876-1971.
Date:
[1906]
Catalogue details

Licence: In copyright

Credit: On variation in the radulae of certain Buccinidae / by M.V. Lebour. 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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    ON VARIATION IN THE RADUL^ OF CERTAIN BUCCINID^. By :sr. V. LEBOUR, B.Sc. (Read before the Society, November 8th, 1905). Plate VI. Varlation in the radula is by no means uncommon in Gastropods. This has been chiefly investigated in Buccinum and its allied genera, many species being easily obtainable. The organ in these cases is simple and large enough to be readily seen, consisting of a long ribbon bearing many rows of chitinous teeth. In the Buccimdte, Fasciolariidse, and others, there is a central plate and one lateral on each side, and these are divided into teeth, which are usually regular throughout the radula. It is the number of these teeth which varies very considerably, both in centrals and laterals, but in the former much more frequently than in the latter. Bateson, in his “ Materials for the Study of Variation,” p. 262, draws attention to Friele’s work on Buccinum, and also refers to information given him by the Rev. A. H. Cooke on this subject. Friele has worked thoroughly on the radula of the Norwegian species of the genus Buccinum (^Jahrb. Deutsch. Mi/l. Ges., vol. 6, p. 257, 1879). In a most elaborate paper he shows how enormously the radula of Buccimim u?idatum varies, and also, in a similar way, other species of the same genus. He regards the radula as of little value for the identification of species in comparison with external characters; closely-allied species, or what authorities have taken to be separate species, not presenting definite differences in the radula. Even in what we take to be distinct genera, we find sometimes that the forms of the radulte merge into each other. For instance, the typical radula in Buccinum undatum has in each row a central plate bearing six teeth and a lateral plate on each side bearing four teeth. The typical form of Neptunea antiqua has a central plate bearing three teeth and a lateral plate on each side bearing three teeth. Now, Bateson gives in his notes above mentioned a figure of a radula of Buccinum undatum, from Labrador, from the collection of the Rev. A. H. Cooke, having three centrals and three laterals on each side through- out, these showing the same form as the typical Neptunea antiqua. This certainly is a very unusual specimen, although Buccinum is extremely variable. Having had exceptional opportunities in the laboratory of Arm- strong College, Newcastle-upon-Tyne, of examining the radula of Buccinum undatum, Neptunea antiqua, and (with fewer specimens) Volutopsis norvegicus, and Bucccinofusus berniciensis, I think the results
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