198 
PALAEONTOLOGY OF NEW YORK. 
HEBERTELLA 
(nom. propos). 
V. Group of Orthis sinuata, Hall. 
PLATE VA, FIGS. 1-13. 
1843. Orthis, Conrad. Proc. Acad. Nat. Sci. Phila, vol. i, p. 333. 
1847. Orthis, Hall. Palaeontology of N. Y., vol. i, pp. 118, 125-128, pi. xxxii, figs. 3,12; pi. xxxiia, fig. 
2 and pi. xxxiib, figs. 1, 2. 
1859. Orthis, Billings. Canadian Nat. and Geol., vol. iv, pp. 435, 436, figs. 11-14. 
1862. Orthis, Billings. Palaeozoic Fossils, vol. i, p. 137, fig. 114. 
1863. Orthis, Billings. Geology of Canada, p. 129, figs. 55, 56 ; p. 167, figs. 148,150 and p. 210, fig. 210. 
1873. Orthis, Meek. Palaeontology Ohio, vol. i, pp. 96, 99, 101, pi. viii, fig. 4, and pi. ix, figs. 1-3. 
1875. Orthis, Miller. Cincinnati Quart. Jour. Sci., vol. ii, pp. 28, 34, 36, 40. 
1875. Orthis, White. Geogr. and Geol. Expl. west 100th Merid. p. 70, pi. iv, fig. 11. 
1881. Orthis, White. Tenth Ann. Rept. Indiana State Geol., p. 117, pi. ii, figs. 10-12. 
1882. Orthis, Whitfield. Geology of Wisconsin, vol. iv, p. 260, pi. xii, figs. 17, IS. 
1882. Orthis, Miller. Journ. Cincinnati Soc. Nat. Hist., vol. v, p. 40, pi. i, fig. 5. 
1883. Orthis, Hall. Rept. N. Y. State Geologist for 1882. pi. xxxiv, figs. 31-34; pi. xxxv, figs. 16-22. 
1884. Orthis, Walcott. Palaeontology Eureka District, p. 74, pi. xi, fig. 6. 
1885. Orthis, Foehste. Bull. Denison University, vol. i, pp. 85, 87, pi. xiii, figs. 13, 15, 16, 20, 21. 
1887. Orthis, Shaler. Memoirs Kentucky Geol. Survey, plate viii. 
1889. Orthis, Nettleroth. Kentucky Fossil Shells, p. 36, pi. xxxiv, figs. 14-20. 
This division is distinguished both by its external and internal characters; 
the pedicle-valve has a well developed, often much elevated cardinal area and 
a long, straight hinge-line ; its surface is depressed-convex, always less convex 
than the opposite valve which is frequently gibbous or inflated. The surface 
is covered with a great number of fine, rounded, closely crowded plications 
which increase rapidly by intercalation, and are crossed by lamellose growth¬ 
lines, and fine concentric striae. On the interior of the pedicle-valve the teeth 
are large and supported by thick lamellae which are continued as a strong ridge 
around a short, obcordate muscular area. This area is medially divided by a 
prominent ridge upon the summit of which lies the linear scar of the adduc¬ 
tors. The flabellate lateral impressions are sometimes divisible into their two 
components, diductors and adjustors, and in old individuals the impression of 
the pedicle-muscle is often distinct. 
In the brachial valve the dental sockets are narrow and are enclosed 
beneath and on the inner side by the strong crural plates. The cardinal 
process is elongate and simple, sometimes thickened, often crenulate, but not 
lobed at its posterior extremity. This process unites with the inner bases of 
