. Bulletin of the British Museum (Natural History). 62 M. G. LOCKLEY & A. WILLIAMS length width BB92461 (12) 20 BB 92462 8-5 9-5 GSM 10889 16-5 180 Figured material Internal and external moulds of Internal and external moulds of p. V. External mould of p. V. Horizon and locality. BB 92461-3 from the Flags and Grits in the middle of the Ffairfach Group, Ffairfach railway cutting, Llandeilo (SN 628211); GSM 10889 probably from the same horizon and locality. Discussion. The brachial valve BB 92461 exhibits pronounced growth distortions on both anterolateral flanks; each side of the valve
. Bulletin of the British Museum (Natural History). 62 M. G. LOCKLEY & A. WILLIAMS length width BB92461 (12) 20 BB 92462 8-5 9-5 GSM 10889 16-5 180 Figured material Internal and external moulds of Internal and external moulds of p. V. External mould of p. V. Horizon and locality. BB 92461-3 from the Flags and Grits in the middle of the Ffairfach Group, Ffairfach railway cutting, Llandeilo (SN 628211); GSM 10889 probably from the same horizon and locality. Discussion. The brachial valve BB 92461 exhibits pronounced growth distortions on both anterolateral flanks; each side of the valve initially grew radially but then irregularly towards the anteromedian and anterolateral sectors of the shell. A single pedicle valve oi'Murinella is known from the Lower Llandeilo Meadowtown Beds of the Shelve area (Williams 1974: 141) and compares with the Ffairfach valve in the arrangement of the muscle field. In the absence of further material, however, it is not possible to do more than conclude that these penecontemporaneous forms may be closely Figs 213-215 Murinella sp. Fig. 213, BB 92462, internal mould of a pedicle valve x 3; Fig. 214, GSM 10889, latex cast of the external mould of a pedicle valve, x 2; Figs 215a, b, BB 92461a, b, internal mould and latex cast of the external mould of a brachial valve, both x 25; all from the Flags and Grits, Ffairfach Group, type section. Subfamily OEPIKINAE Sokolskaya, 1960 Genus MACROCOELIA Cooper, 1956 Macrocoelia llandeiloensis (Davidson) (Figs 216-226) 1871 Strophomena coinpressa (J. de C. Sowerby) var, Llandeiloensis Davidson: 316; pi. 46, figs 11-14. \959 Rafmesquina'] llandeiloensis (DA\'\df,ox\)S'p']e\: 16; pi. 1-7. 1961 Macrocoelia llandeiloensis {Davidson) MacGregor : 206; pi. 23, figs 1-10. Diagnosis. Planoconvex Macrocoelia. becoming slightly geniculate in late adult stages of growth with subperipheral rim; finely ornamented with about 8 parvicostellae per mm, 10 mm anterior of umbo, and with a fla
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