184 DE. T. DAVIDSON OX EECENT BEACHIOPODA. 



Crania anomala, Loven, Index Moll. Scand. p. 29, 1846. 



Crania noiiwgica, Sowerby, Thes. Conch, i. p. 3G8, pi. 73. figs. 15-17, 1847. 



Criopus orcadensis, Leach, Moll. Great Brit. p. 358, pi. xiii. figs. 6-8, 1852. 



Crania anomala, Davidson, Ann. & Mag. Nat. Hist. 2nd ser. vol. ix. p. 376, 1852; Brit. Foss. Brach. 

 Introdnction to vol. iii. p. 123, figs. 44—16, 1853 ; and Mem. See. Linn. Normandie, vol. x. pi. 13. 

 figs. 14-36, 1856; Forbes and Hanley, Brit. Moll. ii. p. 366, pi. Ixi. figs. 7 & 8, 1853. 



Crania norvegica, Carpenter, in Davidson, Br. Foss. Brach. Intr. to vol. i., 1853. 



Crania anomala, L. Barrett, Ann. & Mag. Nat. Hist. 2nd ser. vol. xvi. p. 259, 1855. 



Crania turbinata. Woods, Index Test. ed. Hanley, pi. xi. fig. 2 (not Poli), 1856. 



Crania a7iomala, S.P.Woodward, A Manual of Mollusea, pp. 235,236, figs. 157, 158, 1856; A, 

 Adams, The Genera of Recent Mollusea, p. 583, pi. cxxxii. fig. 3, 1858; E. Suess, Ueber die Wohnsitze 

 der Brachiopoden, Sitznngsb. k. Akad. Wissensch. Wien, Bd. xxxvii. p. 220, 1859 ; Chemnitz, Man. de 

 Conch, ii. p. 230. fig. 1178, 1862 ; L. Reeve, Conch. Icon., Monogr. of Crania, pi. 1. fig. 4, 1862; Gwyn 

 Jeffreys, Br. Conch, vol. ii. p. 24, 1863; and vol. v. pi. xix. fig. 6, 1869; W. King, Trans. Roy. Irish 

 Academy, vol. xxiv. 1869; Dall, Revision of the Craniidte and Discinidse, Bull. IMus. Comp. Zoiil. Har- 

 'vard, vol. iii. p. 32, 1871; and Proc. Acad. Nat. Sci. Philadelphia, p. 198, 1873; G. O. Sars, Moll. 

 Regionis Arcticte Norvegife, ^. 8, 1878. 



Crania anomala, var. alba, Gwyn Jeffreys, Brit. Conch, vol. v. p. 165, 1869. 



Shell hinc^eless, marginally rounded or somewhat squarely orbicular or suTiquad- 

 rate, with rounded angles ; generally wider than long ; posterior border straight or 

 slightly indented, shorter than the breadth of the shell, lateral and front margins 

 gently rounded outwards. Upper valve conical, flattened posteriorly and anteriorly 

 from the apex to the margin. Apex or vertex sometimes sharply hooked and pointed, 

 more or less subcentral or submarginal, surface wrinkled by concentric lines of growth. 

 Colour reddish chocolate-brown or pale or dark liver-colour. Lower valve attached 

 to and moulding itself xipon stones or shells by the whole of its exterior surfoce. 

 In the interior of the ventral or lower valve there exists a wide, flattened, granulated 

 border, sloping upwards and inwards from the margin of the shell with a sharp 

 inclination. At each angle of the posterior inner margin are situated two oblique, 

 widely separated, oval-shaped impressions, left (according to Hancock) by the divaricator 

 muscles ; and near the centre of the bottom of the valve are two contiguous, larger, 

 obliquely placed scars, due to the adductor muscles; between these last and a little higher 

 u]) are two other smaller impressions attributed to the dorsal adjustors. In the interior 

 of the upper or dorsal valve there exists a thin, sharp-edged, granulated margin all round 

 the valve, which fits closely to the sloping margin of the ventral valve and is inwardly 

 limited by a narrow convex ridge which surrounds the interior of the valve. At its 

 inner angles are two almost circular projecting scars, due, according to Hancock, to the 

 divaricator muscles, those scars being widely separated by a concave space ; under these 

 and lower down are two oval-shaped adductor muscular scars, widely separated by a 

 blunt, rounded ridge, wliich extends a little distance towards the front. On each side 

 of its anterior extremity are two small oval-shaped scars, referred by Hancock to the 

 brachial muscles. On the surface of the anterior half of the bottom of tlie valves are 

 seen digitate vascular impressions. The animal is of a white colour, tinged with yellow 

 and l)rown. Mantle very thin, extending to the edges of the valve and closely adhering. 

 Laln'al appendages free, thick, and fleshy, spiral at their extremities, directed towards the 

 concavity of the dorsal valve, and supported by a nose-like prominence in the middle of the 



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