236 PALJEONTOLOGY OF NEW YORK. 



Genus PENTAMERUS, Sowerby. 1813. 



PLATES LXVII, LXVIII, LXIX, LXX. 



1S13. Pentamcriis, J. Sowerby. Mineral Conohulogy, vol. i, p. 76, pi. xxviii. 



1839. Pentamerus, J. dk C. Sowerby. Silurian System, pi. xix, tigs. 9, 10. 



1843. Pmtameru.n, Hall. Geology of New York ; Kept. Fourth Dist., p. 70, figs. 1-5. 



1845. P(7itamems, de Vekneuil. Geologie ile la Russie, p. 119, pi. viii, figs. la-c. 



1852. PCTitamer/M, Hall. PaliEOntology of New Y'ork, vol. ii, p. 79, pi. xxv, figs, lo-m; pi. xxvi, 



figs. 1 a-d ; p. 103, pi. xxxi, fig. 1. 



1854. Pentamenis, Eichwald. Bull. Soc. Imp. Natural. Moscou, pt. 1, p. 91. 



1854. Peiitmner-iLS, F. Schmidt. Neueste Untersuch. ueber Brachiopoden, p. 213. 



1859. Pentamerus, Eichwald. Lethica rossiea, vol. i, p. 788, pi. xxxiv, fig. 23. 



1861. Pujitaiiierus, McChesney. New Palaeozoic Fossils, p. 85. 



1863. Pentainerus, Billings. Geology of Canada, p. 316, fig. 326. 



1866. Pentamerus, Billings. Catalogue Silur. Fossils Anticosti, p. 45. 



1867. Pentamerus, 'Da\id&os. British Siluj'ian Brachiopoda, p. 151, pi. xviii, tigs. 1-12 ; pi xix, tigs. I, 2. 



1867. Pentamerus, Hall. Pala;ontology of New York, vol. iv, pp. 369-374. 



1868. Pentamerus, McChesney. Trans. Chicago Acad. Sci., vol. i, pi. ix, tig. 1. 



1872. Peiitamerm, Hall and Whitfield. Twenty- fourth Ann. Rept. N. Y. State Mus. Nat. Hist., 



p. 183. 

 1875. Pentamerus, Hall and Whitfield. Twenty-seventh Ann. Rept. N. Y. State Mus. Nat. Hist., 



pi. X, figs. 13, 14. 

 1875. Pentamerus, Hall and Whitfield. Paliieontology of Ohio, vol. ii, pp. 137, 139, pi. vii, tigs. 9-11. 

 1882. Pentamerus, Whitfield. Annals N. Y. Acad. Science, vol. ii, p. 195. 

 1882. Pentamerus, Whitfield. Geology of Wisconsin, vol. iv, pp. 288, 291, pi. xvii, figs. 3-9. 

 1889. Pentamerus, Netfelroth. Kentucky Fo.ssil Shells, pp. 60-62, pi. xxix, tigs. 23, 24 ; pi. xxx, 



figs. 2-4. 



1889. Pentamerus, Foerste. Proc. Boston Society Nat. Hist., vol. xxiv, p. 324, pi. v, figs. 17, 18. 



1890. Pentamerus, Whitfield. Annals N. Y. Acad. Sci., vol. v, p. 513, pi. v, figs. 11-22. 



1890. Pentamerus, Gagbl. Die Brachiop. der camb. und silur. Gescbiebe im Diluvium der Provinzen 

 Ost- und Westpreussen, p. 53, pi. iv, fig. 1. 



Since it seems necessary to restrict the term Conchidium to those pentame- 

 roids embraced by de Verneuil in his division " plissus, sans sinus," it becomes 

 desirable to apply the designation Pentamerus to the second division of those 

 shells, the " lisses, sans sinus." This use of Sowerby's term is in precise 

 accordance with recognized rules of nomenclature. The first species cited by 

 Sowerby, and that which has been generally regarded as typical of the genus 

 by authors who have preferred this term to the earlier designation of Linne, 

 is P. Knighti, a plicated shell, which belongs to Conchidium.* The second of 

 Sowerby's typical examples, and that to which must be accorded his generic 



* The P. Aylesfordi, Sowerby, cited in the " Mineral Conchology " as another of the typical species of 

 Pentamerds, was subsequently regarded by that author as a synonym for P. Knighti (Silui-ian System, 

 p. 615, 1839), and the name has consequently fallen into disuse. 



