Memoirs ... Figures and descriptions illustrative of British organic remains. Decade II [VII and XI. Trilobites, with descriptions by J.W. Salter].

  • Geological Survey of Northern Ireland
Date:
1849-1864
Catalogue details

Licence: Public Domain Mark

Credit: Memoirs ... Figures and descriptions illustrative of British organic remains. Decade II [VII and XI. Trilobites, with descriptions by J.W. Salter]. Source: Wellcome Collection.

    57/270
    Decade II. Plate VIII. * CALYMENE TUBERCULOSA. [Genus CALYMENE. Brongnlart. (Sub-kingdom Articulata. Class Crustacea. Order Entomostraca. Family Trilobitse). Axis distinct; glabella lobed, narrower anteriorly ; facial suture dividing the posterior head angles, submarginal in front; a rostral shield ; eyes supine (with a thin cornea ?); thorax of 13 rings, formed for rolling.] Diagnosis. C. lata, depressa, alutacea; margine frontali capitis pro- ducto recurvo, genis gibbosis, glabella depressa; thorace axi angusto, pleuris planis usque ad fulcrum, quod ad dimidium anterius, ad tertium posteri'us, positum est; cauda lata, superne depressa, lateribus abrupte de/lexis ; axi conico, subpiano, 7-8 annulato, costis lateralibus 5, planis, sulcis acutis. Synonyms. C. Blumenbachii vera ? a. tuberculosa, Dalman (1828), p. 36? (not tab. 1, f. 2). C. Blumenb., var. a. tuberculosa. Hisingek (1837), Lethsea Suecica, 10? (not tab. 1, f. 3). C. Blumenb., Murchison, (1839), Sil. Syst., pi. 7, f. 5 only. C. tuberculosa, Salter (June, 1848), “ Memoirs of Geol. Survey,” vol. ii. part 1, pi. 12. Almost every author who has written on Calymene Blumenbachii has hinted his belief that two or more species were to be recognized among its protean forms ; yet, except Colonel Portlock, who separated the C. brevicapitata in his report on the fossils of Tyrone, no one has done more than point out varieties. An extended examination of very numerous specimens convinced us that three distinct species were known in Eng- land, and their characters were detailed in the 2nd volume of the “ Memoirs of the Geological Survey.” Still further investigation of intermediate forms has shaken this opinion again, and we are at present wholly in doubt whether the striking differences about to be pointed out mark only a distinct variety, or are of specific value. At all events, in giving a typical species of this genus, we would rather present the reader with a new and well-marked form, than with one so familiar as that of the famous “ Dudley fossil.” Descriptiaa.—Length, about inches, width, IT inch. Whole sur- face equally and minutely scabrous. General form broad for the genus, not much attenuated posteriorly, depressed. Head short, wide; the
    digitised image 1
    digitised image 2
    digitised image 3