Cryptopecten alli Dall, Bartsch & Rehder, 1938
DALL, W. H., P. BARTSCH & H. A. REHDER. 1938. A manual of the Recent and fossil marine pelecypod mollusks of the Hawaiian Islands. Bernice P. Bishop Museum Bulletin, 153: i-iv, 1-233, pls. 1-58. [p. 93, pl. 23, figs. 1-4, 7]
«Cryptopecten alli, new species (pl. 23. figs. 1-4, 7).
Shell small, alabastine variegated with brown, excepting the blisterlike coverings which are cream yellow. The anterior wing of the right valve bears a well incised byssal notch and is marked dorsally to this by five radiating threads. of which the uppermost is much stronger than the rest and is ornarnented with spikelike scales. The posterior wing is almost as large as the anterior and has four strong scaly radiating cords and three finer ones anterior to these. Both wings are crossed by slender lamellae which bend outward and usually are fused to form hollow chambers. In the left valve the anterior wing bears three strong and five lesser radiating threads, the uppermost ones being strong, while the two succeeding are slender and the fifth being again heavy. Here, too, we have the laminations referred to for the right valve. The posterior wing bears four strong cords and five slender ones. It also shows the concentric scales forming the hollow chambers. The central disk of the shell is marked by a very peculiar sculpture which consists first of 19 radiating ridges. These are decked over by slender lamellae which bend ventrally and fuse with the neighbor, thus forming a series of chambers which give to the rib as a whole, when perfect, the aspect of a median small scaly rachis, with equidistant veins to the right and left. This sculpture, however, is usually present only in patches, being destroyed in the greater part of the shell. Where this outer blister is removed, there is revealed beneath it a strongly keeled median ridge, bordered on each side by a less strong cord, from which spring at regular intervals the lamellae which eventually develop into the blister. So here again we have a plumose effect, showing a scaly rachis with regularly arranged lateral pinnules. The spaces that separate these ribs are not quite as wide as the ribs, and they are marked by five slender radiating threads, which are also connected by slender lamellae which produce a reticulated pattern. This sculpture is characteristic of both valves. The interior of the valves shows the color pattern of the outside and flutings corresponding to the stronger sculpture of the exterior, which terminate in scallops at the ventral margin. The ligamental area is very narrow, and the hinge shows the broad triangular resilial pit with scarcely any indication of a longitudinal last. The hinge area is transversely denticulated in both valves. The byssal notch in the right valve seen from the interior displays a number of fine teeth. The type, U.S.N.M. Cat. No. 173194, was dredged by the U. S. Bureau of Fisheries Steamer Albatross at Station 3811 off the south coast of Oahu in 238-52 fathoms on coarse sand and rocky bottom; surface temperature 74º F. It measures: height, 22.1 mm.; length, 22.8 mm.; diameter of single valve, 3.3 mm. U.S.N.M. Cat. No. 190440 contains a valve dredged by the Albatross at Station 4132 near Kauai in 252-312 fathoms on fine gray sand and mud bottom; bottom temperature 46.8º F. U.S.N.M. Cat. No. 335667, a valve also dredged by the Albatross at Station 4045 off the west coast of Hawaii in 198-144 fathoms on coral, sand and foraminifera bottom; bottom temperature 49º F.» WILLIAM HEALEY DALL, PAUL BARTSCH & HARALD ALFRED REHDER, 1938
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W. H. Dall, P. Bartsch & H. A. Rehder, 1938, plate 23.
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