IXTEODrCTTON. 
XI 
Stroboceras, Hyatt. Type, Gyrocei'as Hartii, Dawson, Acadian Geo- 
logy, 3rd ed. p. 311, fig. 126 (1878). 
Trematodiscns'^, Meek and M’orthen. Type, Nautilus stygialis, dm 
Koninck, Descrip. Anim. Foss. Terr. Carb. de Belgique, pi. xlv. 
(ISW). 
Discitocenis, Hyatt [ = * Disci tes, M‘ C oy]. Type, Discites costellatum , 
M'Coy, S}Tiop. Carb. Foss. Ireland, pi. ii. fig. 4 (1844). 
* Phacoceras, Hyatt. Type, Nautilus oxystojnus, Phillips, Geol. York- 
shire, pt. ii. pi. xxii. (1836). 
Subclymenia, d'Orbigny. Type, Gomatites evolufus, Phillips, Geol. 
Yorkshire, pt. ii. pi. xx. ff. 65-68 (1836). 
Triboloceeatid.s:, Hyatt, 1883. 
Thoracoceras, Fischer deY’aldheim. T}-pe, T. vestitum, Fischer de 'NY. 
Bull. Soc. Imp. Nat. Moscou, yol. xvii. p. 761, pi. xyii. (1844). 
Triboloceras, Hyatt. Type, Gyroceras serratum, de Koninck, De- 
scrip. des Anim. Foss, du Terr. Carb. de la Belgique, pi. xlviii. 
(1844). 
Vestinauiilus, Eyckholt. Type, Nautilus' Eoninckii, d’Orbigny, 
Palieont. Univers. yol. i. pi. xcy. (1847). 
Koninckioceras, Hyatt. Type, Nautilus ingeyis, Martin, Petrificata 
Derbiensia, pi. xli. (1809). \^=Solenocheilus lyentagonus, J. 
Sowerby, sp., see infra, p. 176.] 
Aipoceratidj>, Hyatt, 1883. 
Aploceras, d’Orbigny. Type, Cyrtoceras Verneuiliamnn, de Koninck, 
Descrip, des Anim. Foss, du Ten\ Carb. de la Belgique, pi. xliv. 
(1844). 
*Aipoceras, Hyatt. Tj-pe, Gyroceras gibherosiwi, de Koninck, Faime 
du Calc. Carb. de la Btdgique (Ann. Mus. Boy. d’llist. Nat. de 
Belgique, yol. y.) pt. ii. pi. xxxii. (1880). 
Asymptoceras, Ryckholt. Type, Nautilus cyclostomus, Phillips, Geol. 
Yorkshire, pt. ii. pi. xyiii. f. 3 (1836). 
NAUTiLiDiE, Owen, 1836. 
Sphyrachceras, Hyatt. T^me, Trochoceras Clio, HaU, Pal. New York, 
yol. y. pt. ii. pi. lix. (1879). 
Uranoceras, Hyatt. Type, Cyrtoceras Uranus, Barrande, Syst. Sil. 
Boh. yol. ii. pi. exeyi. (1866). 
* BarrandeoceraSjllyaii. Type, Nautilus natator, Billings, Canadian 
Naturalist and Geologist, yol. iv. p. 466 (1859). 
Pselioceras, Hyatt. Type, Nautilus ophioneus, Waagen, Pal. Indica, 
Salt-Bange Foss. pi. y. (1879). 
Nephriticeras, Hyatt. Type, Nautilus hucinum. Hall, Pal. New 
York, yol. y. pt. ii. pi. lx. (1879). 
^ Professor Hyatt proposed (Genera Foss. Ceph. p. 291, footnote) to change 
this name to Trematoceras. See infra, p. 105 (footnote). 
