Neithea bellulus (Cragin, 1893)
CRAGIN, F. W. 1893. A Contribution to the Invertebrate Paleontology of the Texas Cretaceous. Geological Survey of Texas, Fourth Annual Report, pt. 2, 139-246, pls. 24-45 [p. 216]
1892 Vola bellula Cragin, 1892
Neithea bellula (Cragin); H. T. Kniker, 1919, Comanchean and Cretaceous Pectinidae of Texas, plate 3, figures 3-11.
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«Shell small, thin, nearly equilateral, the height exceeding the length, anterior and posterior margins nearly straight, basal margin describing nearly a semicircle, or with about six very faint prominences corresponding to a similar number of faint or in part obsolete radial undulations of the shell; ears small, unequal; right valve with rather more deeply excavated interior than in similar-sized specimens of Vola texanus, Roem., having a prominently developed, rounded, incurved beak, ornamented with about fifty fine, subequal, rounded or slightly flattened radial ribs separated by narrow sulci, both ribs and sulci appearing smooth to the naked eye, but under the hand-lens seen to be crossed in well preserved specimens with delicate striae; left valve externally fiattish-concave, ornamented with fine radiating costelhe similar to those of the right valve.
Measurements. — Height 20, length 17, breadth 7 mm. Occurrence. — Not uncommon in the Fort Worth limestone. Obtained by L. S. Williams half a mile above the Texas and Pacific railway bridge on Sycamore creek, near Fort Worth, and by the writer at the Sixth (Pecan) street cut of the International and Great Northern railway, at Austin, and on the bluffs of Barton creek.» FRANCIS WHITTEMORE CRAGIN, 1893
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«Shell small, rather slender, very inequivalve right valve very convex and left valve slightly concave; ventral margin almost a semicircle with 6 slight but distinct projecting angles corresponding, with the small principal ribs; ears small, triangular, subequal; surface of each valve marked by 6 slightly differentiated principal ribs, 45 to 50 subequal linear ribs, and by numerous very fine concentric lines of growth. In well-preserved specimens of the convex right valve the principal ribs are represented
by faint angulations which nearly or entirely disappear when the surface is worn or exfoliated. The closely arranged, fine ribs on the convex right valve are somewhat broader than the interspaces, and somewhat narrower on the concave left valve. On the concave valve also the principal ribs are more distinct, forming broad ridges each of which bears 2 or 3 of the linear ribs. A small specimen has the following measurements: Height 26 mm., length 21 mm., convexity 8 mm., hinge line 7 mm., umbonal angle 100°. A larger specimen is 32 mm. in height and 27 mm. in length. Cragin's types are smaller, immature individuals. Types: Three cotypes in Texas State collection at Austin; plesiotypes, U.S.N.M. 103223, 103224a-b. Locality and position: The species appears to be confined to the Fort Worth limestone and upper part of the Duck Creek limestone and their equivalents, and is not very abundant. The material studied by Cragin was from Sycamore Creek near Fort Worth, Tarrant County, and from Austin, Travis County, Tex. Of the specimens here figured, the smallest is from the neighborhood of Bartons Springs near Austin, and the other 2 were collected 10 miles north of Fort Worth. In the Geological Survey collections are specimens from Taylors Creek, Travis County, and from a locality near Denison, Grayson County, Tex.» STANTON, T. W. 1947. Studies of some Comanche pelecypods and gastropods. United States Geological Survey Professional Paper, 211: 1-256, pls. 1-67. [p. 42, 43]
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Pecten (Neithea) bellulus (Cragin); T. W. Stanton, 1947, Studies of some Comanche pelecypods and gastropods, plate 42, figures 3-7.
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