204 
PALAEONTOLOGY OF NEW YORK. 
1775. 
1815. 
1826. 
1827. 
1828. 
1837. 
1537. 
1538. 
1839. 
1842. 
1843. 
1847. 
1848. 
1849. 
1850. 
1852. 
1853. 
1859. 
1859. 
1859. 
1860. 
1869. 
1882. 
1883. 
1884. 
1888. 
1889. 
BILOBITES, Linne. 1775. 
IX. Group of Orthis biloba, Linne. 
Anomia biloba, Linne. 
PLATE Vb, FIGS. 11-19. 
Bilobites, Linne. Systema Naturae, ed. Miiller, vol. vi, p. 325. 
Terebratula, J. Sowerby. Trans. Linn. Soc., vol. xii, p. 516. 
Terebratula, Hisinger. Anteckn. Act. Royal Soc., Holm., pi. 7. 
Belthyris? Dalman. Vetensk. Svenska Akad. Hand., p. 124, pi. 3, tig. 7. 
Belthyris, Hisinger. Bidrag till Sveriges geognosi, vol. iv, p. 220. 
Spirifer, von Buch. Abhandl. Konigl. Akad. d. Wissensch. zu Berlin, p. 49. 
Belthyris, Hisinger. Lethsea Suecica, p. 74. 
Belthyris, Conrad. Second Ann. Rept. Geol. N. Y., pp. 112, 118. 
Terebratula (Belthyris?) Angelin. Museum Palaeont. Suecicum. 
Spirifer, Sowerby. Murchison’s Silurian System, p. 630. 
Belthyris, Conrad. Journ. Acad. Nat. Sci. Phila., vol. viii, p. 262. 
Belthyris, Hall. Geology of N. Y. ; Rept. Fourth District, p. 105. 
Spiriftr, de Vernecil. Bull. Soc. Geol., France, 2d ser., vol. iv. 
Orthis, Davidson. Bull. Soc. Geol., France, 2d ser., vol. v, p. 321. 
Spirifer, Hall. American Journal Science, vol. xx, p. 22S. 
Biccelosia, King. Monogr. Perm. Fossils, England, p. 106. 
Orthis, McCoy. British Palaeozoic Fossils, p. 213. 
Spirifer, Hall. Palaeontology of N. Y., vol. ii, p. 260. 
Orthis, Davidson. Introd. British Fossil Brachiopoda, p. 101, plate viii, figs. 141-145. 
Orthis, Salter. Murchison’s Siluria, 2d ed., p. 543. 
Orthis, Hall. Palaeontology of N. Y., vol. iii, p. 179. 
Orthis, Hall. Twelfth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 85. 
Orthis, Lindstbom. Gotland’s Brach.; Ofver. Kong. Akad. Forhandl., p. 370. 
Orthis, Ramsay and Salter. Mem. Geol. Survey United Kingdom, vol. iii, pp. 267, 361. 
Orthis, Davidson. Trans. Geol. Soc. Glasgow, Pal. Series, vol. i, pi. 2, fig. 2. 
Orthis, Davidson. British Silurian Brachiopoda, p. 206. 
Orthis, Hall. Eleventh Ann. Rept. State Geologist Indiana, p. 286. 
Orthis [Biccelosia ], Hall. Rept. N. Y. State Geologist for 1882, plate xxxv. 
Orthis, Davidson. British Fossil Brachiopoda, General Summary, pp. 377, 433. 
Orthis, Ringueberg. Proc. Acad. Nat. Sci. Phila., p. 134. 
Bilobites, Hall. Bulletin Geological Soc. America, vol. i, p. 21. 
Shells small, strongly bilobed. Hinge-line short; teeth and sockets obscure; 
cardinal process small and simple. Crural plates thin and very long, often 
extending as far forward as the commencement of the lobation. Muscular 
area indistinct, larger in the brachial than in the pedicle-valve. Shell-sub- 
stance fibrous and punctated by coarse tubules apparently arranged in radiat¬ 
ing rows. 
This group comprises but two species, Orthis biloba , Linne and O. varica, 
