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III.—On the Classification of the Terebratellidæ

Published online by Cambridge University Press:  01 May 2009

J. Allan Thomson
J. Allan Thomson
Affiliation:
Director of the Dominion Museum, Wellington, New Zealand.
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Extract

The observations presented by Mr. J. Wilfrid Jackson (1916) on my paper on “Brachiopod Morphology”, published in this Magazine in 1915, are very welcome as furnishing many important details omitted by Davidson and other writers in the description of species. The error into which I fell as regards the types of folding of Dallina and Dalinella illustrates the danger of relying on figures when specimens are not available, but it was worth while making such an error when the correction of it brought forward so many useful observations on other points, particularly on the prevalence of dental plates in the Dallininæ and the relationships of Mühlfeldtia. These observations pave the way for a further advance in the natural or genetic grouping of species and genera. At the same time, while admitting that Dallina is ventrally biplicate, I am not disposed to agree with Mr. Jackson that the folding is exactly comparable to the ventral biplication exhibited in some species of Magellania, but probably arose in a different way. I refrain from a further statement on this point, as I understand that Mr. S. S. Buckman is discussing the subject of types of folding fully in his forthcoming memoir on the Jurassic Brachiopods of Burma. In what follows I shall have again, through lack of specimens in Colonial museums, to rely on figures to some extent, and may possibly again err from this cause, and if so hope the correction will be applied as promptly and informatively as in the former case.

Type
Original Articles
Information
Geological Magazine , Volume 3 , Issue 11 , November 1916 , pp. 496 - 505
Copyright
Copyright © Cambridge University Press 1916

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References

page 496 note 2 References are given in the list of papers at the end of this article, and are indicated in the text by the author's name and date.

page 498 note 1 Anomia sanguinea, Chemnitz, being polynomial, Gmelin's name must be used for this species as Dall has suggested. Beecher's illustrations are based on those of Deslongchamps (1884), who referred to it as Terebratslla sanguinea. It is, of course, a different species from Terebratella cruenta.

page 498 note 2 The earliest stage of Terebratella dorsata described by Fischer and Oehlert (1892), which shows the secondary loop, has a ring on the septum, but I have detected an earlier stage with a hood in T. rubicunda (Thomson, 1915, No. 3).

page 500 note 1 Originally described by Blochmann (1910) as Magasella jaffaensis and ascribed to Campages by Hedley in 1911. Hedley also considered Magellania Joubini, Blochmann, a species of Campages, but this species appears to be correctly placed under Magellania.Google Scholar.

page 501 note 1 Named from Aldinga, South Australia, a notable locality for Tertiary Brachiopods.

page 501 note 2 This term I intended as a (Latin) neuter plural, but in my former paper it was used as a singular noun, and I had not an opportunity to revise the proofs.

page 502 note 1 Two specimens presented to the Dominion Museum, Wellington, by the United States Deep-sea Dredging Expedition off the Coast of Mexico, 1869.

page 503 note 1 It is figured, but not described, by Fischer & Oehlert (1891, pl. v, fig. 10 f.).

page 503 note 2 The beak ridges are poorly defined, and it is difficult to be quite certain of their position. The foramen is certainly not of the submesothyrid type, into which most Terebratellids with lateral deltidial plates fall.