208 THE LIAS AMMONITES. 



Lamarck, 1799. = Angulitlies, Montfort, 1808. = Oceanus, Montfort, 1808. 

 = Ammonites {pars), Montfort, 1808. = Bisiphites {pars), Montfort, 1808. = Con- 

 chyliolithus, Martin, 1809. = Ammonellipsites, Parkinson, 1811. = Ellipsolithes 

 {pars), Sowerby, 1812. = Uhabdites, de Haan, 1825. = Omphalia, de Haan, 

 1825. = Globites, de Haan, 1825. = Aganides {pars), d'Orbigny, 1826. = 

 Aganites {pars), Quenstedt, 1834. = Aturia {pars), Bronn, 1835. = Hamites 

 {pars), Eischer, 1837. = Troeholites {pars), Conrad, 1838. =: Simplegas {pars), 

 Sowerby, 1842. = Discites {pars), M'Coy, 1844. = Discus {pars). King, 1844. 

 ::= Cryptoceras {pars), d'Orbigny, 1850. = Trematodiscus {pars). Meek, 1861. 



Turns {whorls) of the shell, in contact, partially overlapping ; siphuncle almost cen- 

 tral ; aperture of exterior chamber open without folds ; Silurian into Tertiary, still 

 living. 



Ehyncholithes, Eaure-Biguet, 1819. = Conchorhynchus, De Blainville, 1827. 

 = Rhynchoteuthis, d'Orbigny, 1847. 



Comprising the beaks of the Nautilus animal. 



3^2. DiscocEnivs,. Barrande, 1867. 



Turns of the shell touching, siphuncle variable ; aperture of exterior chamber open, 

 its edge not contracted ; Silurian. 



23. Ophidioceras, Barrande, 1867. 



Turns of the shell touching ; siphunclC' variable ; aperture of exterior chamber con- 

 tracted ; Silurian. 



24. Gyroceras, de Koninck, 1844. = Gyroceratites, H. von Meyer, 1829. 

 = Hortolus, Steininger, 1831. = Spirula, Goldfuss, 1832. = Lituites, Quenstedt, 

 1834. = Cyrtocera {pars), Miinster, 1839. = Cyrtoceras {pars), Phillips, 1841. 

 = Cyrthoceratites {pars), D'Archiac, 1842. 



Turns of the shell not in contact ; siphuncle marginal on external (convex) side ; 

 last chamber somewhat small, edge without fold ; from Silurian into Carboniferous. 



2. Shell an arc of a spiral, in the same plane. 



25. Cyrtoceras, Goldfuss, 1832. =: Orthoceratites, Lamarck, 1799. = Ortho- 

 cera {pars), Sowerby, 1812. = Campulites, Deshayes, 1832. = Lituites {pars), 

 Quenstedt, 1836. = Cyrtoceratites, d'Archiac, 1842. = Trigonoceras, M'Coy, 1844. 

 = Campyloceras, M'Coy, 1844. = Aploceras, d'Orbigny, 1850. 



