Cyclochlamys aviculoides (E. A. Smith, 1885)
SMITH, E. A. 1885. Report on the Lamellibranchiata collected by H.M.S. Challenger during the years 1873-76. In C. W. Thomson & J. Murray: Report on the Scientific Results of the Voyage of H.M.S. Challenger during the years 1873-1876. Zoology, 13: 1-341, pls. 1-25 [p. 305, pl. 22, figs. 5-5a]
1885 Pecten aviculoides E. A. Smith, 1885
E. A. Smith, 1885, plate 22.
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«Testa parva, valde inaequivalvis, paulo obliqua, tenuis, sordide albida. Valva dextra planiuscula, nitida, striis incrementi tenuissimis sculpta, sculptura microscopica subreticulata ornata. Valva sinistra profunda, lamellis coucentricis, validis, costisque ad octo radiantibus fortiter cancellata. Auriculae subaequales, auricula valvae dextrae antica lamellis incrementi lirisque paucis radiantibus instructa, inferne subprofunde sinuata. Linea cardinis longa, longitudinem totam testae aequans. Umbones centrales, ille valvae sinistrae paulo supra marginem productus.
This species is remarkable for the great difference in the sculpture of the valves. It is rather like a minute Avicula in form, slightly oblique in growth, very inequivalve, thin, and of a dirty white colour. The right valve is very slightly convex at the centre, and fits, as it were, within the other valve, its very thin margin being upcurved and appressed to the outer edge of the other valve. It is sculptured with a few lines of growth, and has under the microscope a minutely shagreened appearance. The left valve is much deeper, and ornamented with coarse concentric lamellae, which, crossing about seven or eight strongish radiating lirae, produce a coarsely cancellated surface. The ears in this valve have only the concentric lamellae and are about equal in size, the posterior being sinuated at the side. The anterior auricle in the right valve is ornamented with concentric lamellae of growth which cross a few radiating ridges, and it is rather deeply cut in beneath. The hinge-line occupies the whole length of the shell, and above the centre the umbo of the left valve is slightly prominent.
Length 2 mm., height 1¾, diameter ½. Habitat.— Prince Edward Island, in 100 to 150 fathoms. The shell here described is probably not adult; but as the sculpture of the valves is so markedly different and not like that of any other species with which I could compare it, I do not think it hazardous to name it.» EDGAR ALBERT SMITH, 1885
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