DIP. HYO.] 



PTEROPODA. 



391 



trentonensis, Hall, 1847, Pal. N. Y., vol. 



1, p. 222, Trenton and Hud. Riv. Grs. 



triplicata, Swallow, I860, Trans. St. Louis 



Acad. Sci., vol. 1, p. 657, Ham. Gr. 

 undulata, Conrad, 1841, Ann. Rep. N. Y., 

 p. 57, and Pal. N. Y., vol. 5, pt. 2, p. 

 208, Ham. Gr. 



verneuilana, Emmons, 1846, Am. Quar. 

 Jour. Agr. and Sci., vol. 4, p. 330. Sub- 

 carboniferous, 

 victa, White, 1862, Proc. Bost. Soc. Nat. 



Hist., vol. 9, p. 22, Burlington Gr. 

 whitii, Meek & Worthen, 1865, Proc. 



Acad. Nat. Sci., p. 253, Waverly Gr. 

 wilkinsi, Spencer, 1884, Bull. No. 1, Mus. 



Univ. St. Mo., p. 59, Niagara Gr. 

 DIPLOTHECA, Matthew, 1885, Am. Jour. Sci. 

 and Arts, 3d ser., vol. 30, p. 293. [Ety. 

 diploos, double ; Theca, a genus.] Slen- 

 der, conical, section triangular ; internal 

 septa dividing it in segments ; body 

 cavity separated from one side by a 

 thin partition, supported by delicate 

 transverse septa ; distinguished from 

 Hyolithes by more rapidly expand- 

 ing, and by a firmer, rounder side, 

 where it has the support of the lateral 

 septa. Type D. acadica. 

 acadica, Matthew, 1885, Am. Jour. Sci. 

 and Arts, 3d ser., vol. 30, p. 294, St. 

 John Gr. 



hyattana, Matthew, 1885, Am. Jour. Sci. 

 and Arts, 3d ser., vol. 30, p. 294, St. 

 John Gr. 



hyattana var. caudata, Matthew, 1885, 

 Am. Jour. Sci. and Arts, 3d ser., vol. 

 30, p. 294, St. John Gr. 

 HYOLITHELLUS, Billings, 1871, Can. Nat. 

 and Geol, vol. 6, p. 240, and Am. Jour. 

 Sci. and Arts, 3d ser., vol. 3, p. 360. 

 [Ety. diminutive of Hyolithes.] Dis- 

 tinguished from Hyolithes by its long, 

 slender form and structure of the oper- 

 culum. Type H. micans. 



micans, Billings, 1871, Can. 

 Nat. and Geol., vol. 6, 

 p. 240, and Am. Jour. 

 Sci. and Arts., 3d ser., 

 vol. 3, p. 354, Up. Ta- 

 conic. 



micans var. rugosa, Wal- 

 cott, 1887, Am. Jour. Sci. 

 and Arts, 3d ser., vol. 34, 

 p. 191, Up. Taconic. 

 HYOLITHES, Eichwald, 1840, 

 Sil. Scbicht. Syst. in 

 Ehstl., p. 97. Appar- 

 ently the internal casts 

 of tubes forming an 

 elongate, subtriangular 

 pyramid ; lateral margins 

 acute and tapering from 

 the base to an acute extremity ; dorsal 

 side usually more convex than the ven- 

 tral, and often longitudinally sinuate; 

 aperture usually oblique and extended 

 on the ventral side ; surface smooth, or 

 having arching or transverse striae. 

 Type H. acutus. 



FIG. 645,-Hyoli- 

 thellus micans. 

 Terminal por- 

 tion enlarged. 



aclis, Hall, 1876, Illust. Devonian Foss., 



pi. 27, and Pal. N. Y., vol. 5, pt. 2, p. 



197, Ham. Gr. 

 aculeatus, Hall, 1860, (Theca aculeata,) 



13th Rep. N. Y. St. Mus. Nat. Hist., p. 



107, Kinderhook Gr. 

 americanus, Billings, 1871, (Theca trian- 



gularis,) Hall, Can. Nat. and Geol., vol. 



6, p. 213, Up. Taconic. 

 baconi, Whitfield, 1878, Ann. Rep. Geo. 



Sur. Wis., p. 77, and Geo. Wis., vol. 4, 



p. 225, Trenton Gr. 

 carbonaria, Walcott, Monogr. U. S. Geo. 



Sur., vol. 8, p. 264, Subcarboniferous. 

 centennialis, Barrett, 1877, Ann. Lye. 



Nat. Hist., vol. 11, p. 299, Low. 



Held. Gr. 

 communis, Billings, 1871, Can. Nat. and 



Geol., vol. 6, p. 213, Up. Taconic. 

 danianus, Matthew, 1884, Bull. U. S. Geo. 



Sur., vol. 2, p. 283, St. John Gr. 

 emmonsi, Ford, 1873, Am. Jour. Sci., 3d 



ser., vol. 5, p. 214, Up. Taconic. 

 excellens, Billings, 1874, Pal. Foss., vol. 



2, p. 70, Up. Taconic. 

 gibbosus, Hall & Whitfield, 1873, 23d Rep. 



N. Y. St. Mus. Nat. Hist., p. 242, Pots- 

 dam Gr. 

 gracilis, Matthew, 1885, (Camerotheca 



gracilis,) Can. Rec. Sci., vol. 1, p. 149, 



St. John Gr. 

 gregarius, Meek & Hayden, 1861, Proc. 



Acad. Nat. Sci. Phil, p. 436, and Pal. 



Up. Mo., p. 5, Potsdam Gr. 

 heros, Hall, 1888, Pal. N. Y., vol. 7, p. 7, 



Low. Held. Gr. 

 impar, Ford, 1872, Am. Jour. Sci., 3d ser., 



vol. 3, p. 419, Up. Taconic. 

 ligea, Hall, 1863, (Theca ligea,) 15th Rep. 



N. Y. St. Mus. Nat. Hist., p. 62, and 



Pal. N. Y., vol. 5, pt. 2, p. 195, Up. 



Held. Gr. 



micans, see Hyolithellus micans. 

 micmac, Matthew, 1884, Bull. U. S. Geo. 



Sur., vol. 2, p. 283, St. John Gr. 

 neapolis, Clarke, 1885, Bull. U. S. Geo. 



Sur., No. 16, p. 56, Portage Gr. 

 parviusculus, Hall, 1862, (Theca parvius- 



cula,) Geo. Rep. Wis., p. 425, Hud. 



Riv. Gr. 

 primordialis, Hall, 1861, (Theca primor- 



dialis,) Geo. Rep. Wis., 



p. 48, and Geo. Wis., vol. 



4, p. 175, Potsdam Gr. 

 princeps, Billings, 1871, 



Can. Nat. and Geol., vol. 

 6, p. 213, and Am. Jour. 

 Sci. and Arts, 3d ser., 

 vol. 3, p. 355, Up. Ta- 

 conic. 



principalis, Hall, 1876, Il- 

 lust. Devonian Foss., pi. 

 27, and Pal. N. Y., vol. 



5, pt. 2 p. 196, Scho- 

 hane grit. 



shaleri, Walcott, 1885, Bull. 



U. S. Geo. Sur., p. 283, Up. Taconic. 

 singulus, Hall, 1879, Pal. N. Y., vol. 5, pt. 



2, p. 202, Ham. Gr. 



