. Bulletin - New York State Museum. Science. NIAGARA FALLS AND VICINITY 201 Genus tremato3pira Hall [Kty.: Tfr/^fia, foramen; ^-cT/va, spire] (1859. A^. Y. state vius. nat. hist. 12th an. reft, p. 27; 1893. Pal. N. Y. V. 8, pt 2, p. 124) Shells transverse, with siibequally convex valves; surface radially plicate; hinge line straight, cardinal extremities abruptly rounded; anterior margin sinuate. Pedicle valve with a median sinus and an incurved beak, truncated by a circular foramen. Delthyrium cov- ered by two short incurved plates, which are usually closely an- kylosed, and appear continuous
. Bulletin - New York State Museum. Science. NIAGARA FALLS AND VICINITY 201 Genus tremato3pira Hall [Kty.: Tfr/^fia, foramen; ^-cT/va, spire] (1859. A^. Y. state vius. nat. hist. 12th an. reft, p. 27; 1893. Pal. N. Y. V. 8, pt 2, p. 124) Shells transverse, with siibequally convex valves; surface radially plicate; hinge line straight, cardinal extremities abruptly rounded; anterior margin sinuate. Pedicle valve with a median sinus and an incurved beak, truncated by a circular foramen. Delthyrium cov- ered by two short incurved plates, which are usually closely an- kylosed, and appear continuous, with a narrow, flattened area on either side; lower half of the delthyrium open, for the reception of the beak of the brachial valve. Teeth prominent, arising from the bottom of the valve; above the hinge line they curve backward and toward each other, thus making a very firm articulation. Muscular area well defined. Brachial valve with median fold, and minute beak. Hinge plate greatly elevated, with a small chilidium resting against it; upper face of plate deeply divided by median longitudinal groove, and more faintly by transverse groove. Dental sockets small and deep, crura broad, thin and comparatively short. Brachi- dium of two spiral cones set base to base, as in S p i r i f e r . Trematospira camura Hall (Fig. 122). Atrypa camura Hall (1852. Pal. N. Y. 2:273, pi. 56) "^1^^ .4^, Distinguishing characters. Small; subrhomboidal to transversely elon- gate; nearly equally convex valves. Small, acute, proiectins: and slip"htlv in- ^ -^ "^ o . pjg^ J23 Trematospira camura curved beak of pedicle valve, showing in young shells the ankylosed deltidial plates; strong, distant, simple subangular plications, one or two fine ones in the center; fine, thread-like concentric striae and coarse lamellae. Found in the Bryozoa beds of the Rochester shale at Niagara, rather common. Also at Lockport and elsewhere (Hall). Genus whitfieldella Hall & Clarke [Ety.: proper nam
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectscience, bookyear1887
