. Bulletin - New York State Museum. Science. 1050 NEW YORK STATE MUSEUM Width 10 mm, hight 9 mm, thickness 6 mm. [Am. Mus. cat. no. I-5/-3- ] This compares quite well with a typical 0. n e g 1 e c t a from the Niagaran of Lockport1 except that the Lockport specimen has only six lateral plications on the pedicle and five on the brachial valve on each side. It differs as widely from the ordinary specimens of C. n e g 1 e c t a as does C. hudsonica. Rhynchospira excavata General form and proportions as in R. f o r m o s a Hall, of the Helderbergian. The present species is however very con
. Bulletin - New York State Museum. Science. 1050 NEW YORK STATE MUSEUM Width 10 mm, hight 9 mm, thickness 6 mm. [Am. Mus. cat. no. I-5/-3- ] This compares quite well with a typical 0. n e g 1 e c t a from the Niagaran of Lockport1 except that the Lockport specimen has only six lateral plications on the pedicle and five on the brachial valve on each side. It differs as widely from the ordinary specimens of C. n e g 1 e c t a as does C. hudsonica. Rhynchospira excavata General form and proportions as in R. f o r m o s a Hall, of the Helderbergian. The present species is however very con- vex in the umbonal region, and the cardinal slopes of both valves strongly excavated, a feature which recalls more nearly Camarotoechia than Rhynchospira. The beak of the pedicle valve is strongly incurved over that of the brachial. The apical portion is broken away in the only specimen known so far. The posterior lateral margins of the pedicle valve have a gentH concave outline to almost the middle of the valve, beyond which they round regularly to the front. In the brachial valve the posterior lateral margins form a nearly straight line. A shallow median depres- sion begins at the beak of the pedicle valve and grad- ually widens forward, hav- ing in each stage of growth about twice the width of the spaces between the plications. The bottom of the depression is rounded, becoming flatter toward the front. It is margined on each side by a plication, which is somewhat weaker than those covering the remainder of the shell. The latter are sharply rounded and at intervals appear subnodose in the exfoliated shell, this feature being caused by strong concentric striae. There are in all nine plications on each side of the median line; two of these are very faint and short and occupy the depressed cardinal slopes. In the brachial valve a faint plication marks the center and corresponds to the depression of the pedicle valve. On each side of this are seven plications, the interspace 1
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