Cyclopecten ringnesia (Dall, 1924)
DALL, W. H. 1924. Supplement to the Report of the Canadian Arctic Expedition, 1913-18, Volume VIII, Part A, Mollusks, Recent and Pleistocene (1919). In Report of the Canadian Arctic Expedition, 1913-18: 31A-35A, pl. 4. F. A. Acland, Ottawa, Canada. [p. 32A, pl. 4]
1924 Pseudamusium [sic] ringnesia Dall, 1924
W. H. Dall, 1924, plate 4.
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«Shell small, translucent white, extremely thin, nearly fiat; disk nearly circular, sculptured with about 30 thin, sharp, regularly concentric lamellae with much wider interspaces; the outer edge of these lamellae is produced and bent down but not attached at the distal edge, covering about two-thirds of the interspace in front of the lamella; these loose margins are somewhat wavy and narrower posteriorly and stop short on a line radiating from the umbo toward the posterior base; at the point of termination they expand into postules forming a line bordering a posterior area, sculptured only by close, low, concentric lamellation; the true surface of the valve is not undulated but sculptured with fine radial striae; the whole of this lamellation is of extreme fragility and liable to be affected by a touch; the hinge margin is straight, the anterior ear larger than the posterior, with a close, minute, subspinose, concentric lamellation: the posterior ear with only lines of growth; the hinge is minute, the interior of the disk smooth, the external sculpture showing through. Height 12 mm.; breadth 13 mm.
Only one left valve was obtained but the sculpture is quite unique and the shell is not undulated, the appearance of undulation arising from the foldedover edges of the lamellae. Type.— Victoria Memorial Museum, Ottawa (Mollusks, No. 4376). Figured on Plate 4.» WILLIAM HEALEY DALL, 1924
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