Parvamussium holmesii (Dall, 1886)
DALL, W. H. 1886. Report on the Mollusca, Part I. Brachiopoda and Pelecypoda. Reports on the results of dredging, under the supervision of Alexander Agassiz, in the Gulf of Mexico (1877-78) and in the Caribbean Sea (1879-80), by the U.S. Coast Survey Steamer “Blake”…. Bulletin of the Museum of Comparative Zoology at Harvard University, 12: 171-318, pls. 1-9. [p. 214, pl. 5, figs. 5, 11]
1886 Amusium (Propeamusium) [sic] holmesii Dall, 1886
W. H. Dall, 1886, plate 5.
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«Shell small, somewhat oblique, thin, brightly colored (like A. var. marmoratum), the convex valve with twenty to twenty-eight faint radiating ridges, absent toward the beaks and with intercalary ridges toward the margin; interspaces between the ribs polished, mostly smooth or with traces of concentric lamellae which near and over the radiating ridges rise to arched scales, which in some cases are closed in front, forming spindle-shaped pustules, with the longer axis in the concentric line to which they belong; anterior ear the larger, pectinately scaled on the margin, with obscure radiating or lamellar sculpture; concave valve finely concentrically waved, the waves becoming crowded and scaly toward the margin ; anterior ear with three or four radiations and strong lamellae, posterior ear lamellate, but not radiated; anterior margin rounded, posterior ditto, produced. Alt. 12.0, Ion. of shell 12.0, of hinge line 6.0, max. diam. 2.0 mm. Internal lirae eleven to fourteen, fine, with a tendency to pair, and falling considerably short of the margin in the completely adult shell.
Dredged at Station 273 in 103 fms., and in 100 fms. at Barbados, living. The bottom was yellow coral and broken shell, and the temperature 59°.5 F. This pretty shell is nearest A. Hoskynsi Forbes, from which it differs by the polished umbonal region, the larger number of ribs, the smaller size and different shape of the pustular scales, by its larger size, differently proportioned and pectinated ears, and by the strength, number, and character of its internal lirae. Its form is nearest that of A. Pourtalesianum, var. marmoratum, which is also brightly colored. It is named in honor of Dr. Holmes, the author of the "Pliocene Fossils of South Carolina."» WILLIAM HEALEY DALL, 1886
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