Chlamys suprasilis Finlay, 1928
FINLAY, H. J. 1928. The recent Mollusca of the Chatham Islands. Transactions and Proceedings of the Royal Society of New Zealand, 59: 232-286. [p. 269, plate 43, figures 52-55.]
«Chlamys suprasilis n. sp. (Figs. 52, 53, 54, 55).
At first sight merely a worn celator, but the scaling is different. Shell almost exactly like celator in habit and style of sculpture, but relatively a little wider and more compressed vertically, the basal margin being less convex and shorter, and the dorsal margins meeting at a wider angle. Both valves less convex, especially the right, which, in its early stages is generally flattish or even concave. Typically, spinous sculpture is obsolete over most of the shell, the strong main ribs (double in the right valve) present as in celator, but with only one fairly strong interstitial riblet, and all ribs and interstices perfectly smooth and polished, as if secondary sculpture had been heavily erased. This stage may last over the whole shell; more frequently there are a few sparse scales towards the lower margin, or the smooth area may cease suddenly and give way to a spinose surface just as in celator; occasionally spinose sculpture may be developed over most or all of the surface. The scales, however, are of a different style, not close, high, and narrowly spout-like, situated on sharply angular ribs, but rather distant, low, broadly subtubular, and placed on wide, rounded ribs. The ears of both species are spinose, but the same difference in the scales is observable. Length, 33 mm.; height, 33 mm. Locality: Port Chalmers, near Dunedin (type and others, from rubbish scraped from the botton of a ship which had been in dock for several years); Dowling Bay, Dunedin Harbour, attached to stones at low water mark; Taieri Beach; Chatham Is., not uncommon. Fossil at Castlecliff. It is often difficult to assign beach-worn valves to celator or suprasilis with certainty, but fresh specimens are easily separated. In colour the two new species show the same variation as is seen in zelandiae; it has not been thought worth while to detail it.» HAROLD JOHN FINLAY, 1928
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H. J. Finlay, 1928, plate 43.
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