Pallium kapitiensis Mestayer, 1929
MESTAYER, M. K. 1929. Notes on New Zaland Mollusca. Nº 4. Transactions and Proceedings of the New Zealand Institute, 60: 247-250, pls. 20-25. [p. 249, pl. 25, figs. 18, 19]
«Pallium Kapitiensis n. sp. figs. 18-19.
Valves, rather flattened; right valve: 4 strong broadly rounded folds with slight trace of a 5th near anterior edge; left valve: the 5th fold is much stronger on this valve. Both valves covered with fine sharp radial riblets 89-90 on each valve, interstices vary slightly in width, but most are rather wider than the riblets. On the main folds the riblets show a tendency to be slightly stronger and coarser than elsewhere: those on the left valve being slightly coarser than on the right, with a tendency towards bifurcating. Valves closely covered with dense semi-microscopical growth striae, with irregular, more or less strongly Inarked rest periods. Apical parts polished, radial folds, riblets hardly showing. Ears, unequal, posterior smaller, outline more concave. Right valve anterior ear 5 fairly strong ribs, marked off from valve by a well marked groove; ctenidium with 5 minute sharp teeth. Posterior ear, 5 ribs crossed by fine growth lines several of which are so strong as to suggest their being rest periods. The posterior margins of both ears sharply denticulate by the growth lines. Left valve, anterior ear 4 ribs, also crossed by growth lines, byssal aperture and ctenidium, quite covered; junction with valve grooved. Posterior ear with four primary radials the lower two nluch weaker; in each interstice is a fine thread and on the disc side of the lowest primary are two threads, near body of valve 3 rather fine threads. Posterior margins of ears almost smooth, edges gaping posteriorly; closely appressed anteriorly, byssal opening small, on right valve only. The shell appears to have lain on its right valve, probably on a sandy ground, as that valve is entirely free from extraneous growths, while there are remains of several small colonies on the left valve. Colour, lemon yellow. A juvenile from near Hen and Chicken Island is pinkish orange. Umbos, minute, smooth, polished for first 2 mm. Ligament, internal, a small resilium under the umbo, faint vertical numerous ridges below hinge line. lnterior of both valves slightly pearly especially along the pallial line. From the pallial line to the margins the radial threads show as fine grooves. Muscle Scar, nearly round, sub-central. Colour—right valve whitish, anterior margins tinged lemon yellow; left valve, inside of pallial line pale pinkish, anterior margin up to pallial line distinctly lemon yellow. General outline triangular, with wavy convex anterior margin. The main folds and sulci alternate; the folds on one valve fitting the sulci on the other. Measurements: Length 31 mm. Breadth 35 mm. Thickness 9 mm. Hinge Line 21 mm. Locality: Off Kapiti Island; taken out of the stomach of a blue cod, caught in about 3 fathoms, by Messrs. Watson Bros. of Waikanae, who kindly presented it to the Dominion Museum. Also a broken, and a juvenile specimen, from near Hen and Chicken Islands. Remarks: This species is comparable with Pallium convexum (Q. & G.) as figured in voyage of "Alstrolabe," the folding being very similar and the sculpture almost identical; but the radial riblets in P. convexum are broader and flatter, and at the same growth stage much fainter than P. kapitiensis. Also the posterior ear is smaller and joins the disc almost vertically, while in P. kapitietnsis there is a distinct inwards curve.» MARJORIE K. MESTAYER, 1929 |
M. K. Mestayer, 1929, plate 25.
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