BRACHIOPODA. 13 



(1) 1863. Spirifera, Halt.. Ti-ansactions of the Albany Institute, vol. iv, p. 211. 



(1) IStiS. Spirifer, Billings. Geology of Canada, p. 317, fig.s. 328 a, h ; p. 957, fig. 4m; and Proc. 



Portland Soc. Nat. Hist, p, 117, pi. iii, fig. 16. 



(2) 1863. Spirifer, Billings. Geology of Canada, p. 317, fig. 329. 



(1) 1866. Spirifer, Billings. Catalogue Silurian Fossils Aiiticosti, p. 48. 



(1) 1867. Spirifera, Hall. Twentielh Annual Report N. Y. State Cab. Nat. Ilistoi-y, p. 370. pi. xiii, 



tigs. 5, 7; p. 371, pi. xiii, figs. 9-11. 



(3) 1867. Spirifera, Hall. Twentieth Annual Report N. Y. State Cab. Nat. History, p. 372, pi. xiii, 



figs. 14-16. 



(2) 1867. Spirifera, Hall. PaliBontology of N. Y., vol. iv, p. 218, pi. xxxv, figs. 1-9; p. 242, pi. x1, 



fitjs. 14-22. 



(3) 1868. Spirifera, McChesney. Trans. Chicago Acad. Sci., vol. i, p. 35, pi. viii, fig. 3. 

 (1) 1872. Spirifera, Hall. Twenty-fourth Ann. Kept. N. Y. State Mus. Nat. Hist., p. 182. 



(1) 1875. Spirifera, Hall and Whitfield. Twenty-seventh Ann. Rept. N. Y. State Mus. Nat. Hiat., 



pi. ix, figs. 11, 13, 17, 18. 

 (1) 1879. Spirifera. Hall. Twenty-eighth Ann. Rept. N. Y. State Mus. Nat. Hist., p. 156, pi. xxiv, 



figs. 13-18 ; p. 157, pi. xxiv, figs. 20-30. 

 (1) 1880. Spirifera. White. Second Ann. Rept. Indiana Bureau of Statistics and Geol., p. 497, pi. iii, 



figs. 5, 6. 

 (1) 1881. Splrifei-a, White. Tenth Ann. Rep., Slate Geologist Indiana, p. 129, pi. iii, figs. 5, 6. 

 (1) 1882. Spirifera, Hall. Eleventh Ann. Rept. State Geologist Indiana, p. 294, pi. xxiv, figs. 13-18 ; 



p. 296, pi. xxiv, figs. 20-30. 



(1) 1882. Spirifera, Whitfield. Geology of Wisconsin, vol. iv, p. 287, pi. xvii, figs. 1, 2. 



(2) 1885. Spirifera, Clakkb. Bull. U. S. Geol. Survey, No. 16, p. 30, pi. iii, fig. 13. 



(2) 1886. Spirifera, Ringuebbrq. Bull. Buffalo Soc. Nat. Hist., vol. v, p. 16, pi. ii, fig. 5. 

 (1) 1889. /Spiri/er, Beecher and Clarke. Mem. N. Y. State Museum, p. 78, pi. vi, tigs. 9-11. 

 (1) 1889. Spirifera, Nettelroth. Kentucky Fossil Shells, p. 117, pi. xxxii, figs. 28-31 ; p. 129, 

 pi. xxiv, fig. 25 ; pi. xxvii, figs. 17-19 ; p. 130, pi. xxix, figs. 13-16. 



(1) 1890. Spirifera, Foerste. Proc. Boston Soc. Nat. Hist., vol. xxiv, p. 313, pi. v, tig.s, 5, 6. 



(2) 1891. Spirifer, Whiteaves. Contributions to Canadian Palseontology, vol. i, p. 224, pi. xxxii, tig. 1. 



Smooth, radially undulated or plicated; fold and sinus smooth; entire 

 surface covered with fine, filiform, radiating striae, which may be minutely 

 crenulated or granulose. 



This group includes shells which may vary considerably in the length of the 

 hinge and the degree of plication. Spirifer radiatus is frequently, and in 

 American faunas usually devoid of plications, but the assumption of these 

 characters is so gradual a process that there is no satisfactory distinction, in a 

 large number of examples, between the smooth form and the typical plicated 

 form of S. plicatellus. The plications are, however, never numerous or sharply 

 defined. 



These radiate shells may be conveniently subdivided as follows : 

 1. Pauciplicati, or those with few low plications; as Spirifer radiatus, Sowerby, 

 S. Eudora, Hall, from the Clinton and Niagara faunas, and S. macropleura, Con- 



