POL. SOI,.] 



CEPHALOPODA. 



453 



ellipticum, Hall & Whitfield, 1875, Ohio 



Pal., vol. 2, p. 152, Niagara Gr. 

 expansum, Winchell, 1863, Proc. Acad. 



Nat. Sci., p. 23, Kinderbook Gr. 

 hector, Billings, 1862, Pal. Foss., vol. 1, p. 



163, Guelph Gr. 

 hoyi, Whitfield, 1878, Ann. Rep. Geo. Sur. 



Wis., p. 86, and Geo. Wis., vol. 4, p. 300, 



Niagara Gr. 



FIG. 757. Phragmoceras hector. Side view. 



hoyi var. compressum, Whitfield, 1878, 

 Ann. Rep. Geo. Sur. Wis., p. 82, and 

 Geo. Wis., vol. 4, p. 301, Niagara Gr. 

 labiatum, Whitfield, 1878, Ann. Rep. Geo. 

 Sur. Wis., p. 86, and Geo. Wis., vol. 4, 

 p. 302, Niagara Gr. 

 nestor, Hall, 1867, 20th Rep. N. Y. Mus. 



Nat. Hist., p. 405, Niagara Gr. 

 nestor var. canadense, Whiteaves, 1884, 



Pal. Foss., vol. 3, p. 39, Guelph Gr. 

 parvum, Hall & Whitfield, 1875, Ohio 



Pal., vol. 2, p. 151, Niagara Gr. 

 prsematurum, Billings, 1866, Can. Nat. 

 and Geo., vol. 5, p. 173, Black Riv. and 

 Trenton Grs. Type of Hyatt's genus 



Mselnoceras. 

 spinosum, see Gyroceras 



spinosum. 



walshi, Meek & Worthen, 

 1866, Proc. Acad. Nat. 

 Sci. Phil., p. 257, and 

 Geo. Sur. 111., vol. 6, p. 

 511, Ham. Gr. 

 PILOCERAS, Salter, 1859, 

 Quar. Jour. Geo. Soc., 

 vol. 15, p. 376. [Ety. 

 pilos, a cap ; &mis,horn.] 

 Broad, conical, slightly 

 curved, subcylindrical 

 or compressed; siph un- 

 cle and septa combined 

 as a series of conical, 

 concave septa, which 

 fit into each other 

 sheathwise. Type P. 

 invaginatum. 

 ainplum, Dawson, 1881, Can. Nat., vol. 10, 

 p. 1, Calciferous Gr. 



FIG. 758. Pilo- 

 ceras wortheni. 



canadense, Billings, 1860, Can. Nat. and 

 Geol., vol. 5, p. 171, Calciferous Gr. 



explanator, Whitfield, 1886, Bull. Am. 

 Mus. Nat. Hist., vol. 1, p. 323, Birds- 

 eye Gr. 



gracile, Billings, 1865, Pal. Foss., vol. 1, 

 p. 257, Quebec Gr. 



triton, Billings, 1865, Pal. Foss., vol. 1, p. 

 257, Quebec Gr. 



wortheni, Billings, 1865, Pal. Foss., vol. 1, 



p. 256, Quebec Gr. 



Polycronites haani, Troost, 1840, 5th Geo. 

 Rep. Tenn., Devonian. Not clearly 

 defined, but probably a Gyroceras. 

 PTERONAUTILUS, Meek, 1864, Pal. of Up. Mo., 

 p. 64. [Ety. pteron, wing; Nautilus, a 

 genus.] Shell with the involute body 

 portion comparatively very small, and 

 globular in form, scarcely umbilicate ; 

 outer chamber very large, and deflected 

 from the involute body, its inner or 

 ventral side being widely open, and the 

 lateral margins greatly dilated, so as to 

 form a very large, wing-like expansion 

 on each side. Type P. seebacbanus. 



seebachanus, Geinitz, (Nautilus seebach- 

 anus,) Garb, und Dyas, p. 43, Per- 

 mian Gr. 



S^RICHNITES, Billings, 1866, Catal. Sil. Foss. 

 Antic., p. 73. The author supposed the 

 tracks might have been made by a spe- 

 cies of Cephalopoda. They consist of 

 two parallel rows of semicircular or 

 subquadrate pits ; each pit is about one- 

 half inch in diameter, and separated 

 from the succeeding one by about one- 

 fourth of an inch. Type S. abruptus. 



abruptus, Billings, 1866, Catal. Sil. Foss. 



Antic., p. 73, Hud. Riv. Gr. 

 Sidemina infundibuliforme, Castelnau, 1843, 

 Syst. Sil., p. 33. Probably the fragment 

 of an Endoceras. 



SOLENOCHILUS, Meek & Worthen, 1870, Proc. 

 Acad. Nat. Sci. Phil., vol. 20, p. 47. 

 [Ety. mien, a channel ; cheiJos, a lip.] 

 Nautiloid in form, with small siphuncle 

 in contact, or nearly in contact, with 

 the outer shell ; margins of the lip near 

 the umbilicus, terminating in spout- 

 like auricles. Type S. collectum. 



FIG. 759. Solenochilusavonense. 



avonense, Dawson, 1868, (Nautilus avon- 

 ensis,) Acad. Geol., p. 311, Carbonif- 

 erous. 



