150 
TJie American Grohujixt. 
March, ISWl 
Tremiitis, Sharpe 1847. 
Orbicella, d'Orbigiiy 1^47. 
uSchizocrania, TTall and Whit- 
field 1875. 
(Ehlertella. Hall 18U0. 
LiiigulodisciTia,AVhitfield '90. 
? Monol)oliiia. Salter ISOo. 
■Orbiculoidea. dOrbigny 1847 
Schizotreta, Kutorga 1848. 
Lindstnemella, Hall 18!J(l. 
Rfemerella, Hall 18!»0. 
'1. Family Discinid.^, tira}- 184(1. 
Orbic-ulidif, .McCoy 1844. 
Disciua, Lamarck 1819. 
Orbicuia, Sowerby 1880 (not 
(■uvier 1798). 
Discinisca. Dall 1871. 
2'. Family Acrotrktiij/E, n. fam. 
Iphidea, Billings 1872. 
Acrothele, Linnarsson 187(5. 
Linnarssonia, Walcott 1885. 
Discinopsis (Matthew). Hall 
1892. 
:>. Family Sii'Iionotretid.e, Kutorga 1848 
Acrotreta, Kutorga 1848. 
Conotreta, Walcott 1889. 
? Mesotreta, Kutorga 1848. 
? A'olborthia, von M()ller 1873. 
Siphonotreta, de Verneuil 1845- 
^Schizambon, Walcott 1884. 
Scliizambonia, (Khiert 1887. 
? Keyserlingia, Pander 1861. 
? Helmersenia. Pander 18»)1. 
Suborder Gasteropeg'mata, Waagen 1885. 
Family Cramih.e, King 1846. 
Orbiculse, Deshayes 1830; (' ran iadie, Gray 1840. 
•C'rania, lletzius 1781. 
Nuininulus, Stobivus 1732. 
Crioptis, Poll 1791. 
( 'riopodernia, Poll 1795. 
Orbicuia, Cuvier 1798 (not 
Sowerby 1830). 
Orbicularius, Dunieril 1806. 
■Craniolites, Schlotheim 1820. 
Discina, Turton 1882 (not 
Lamarck 1819). 
'Criopodt)derma, Agassi/. 1846. 
Clioniopora, Scliaurotli 1854. 
(h-aniella, (Ehlert 1888. 
Cardinocrania, Waagen 1885. 
Ancistrocrania, Dall 1877. 
Cranopsis, Dall 1871 (not A. 
Adams). 
Craniseus, Dall 1871. 
Siphonaria, Quenstedt 1851 
(not Sowerby). 
Pholidops, Hall 1860. 
(!raniops. Hall 1859. 
Pscudocrania, McCoy 1851. 
Pahfocrania, C^uenstedt 187! • 
Subclass ARTHROPOMATA, Owen 1858. 
Helictopoda (part), Sarcicobrachia (part), Ancylopoda and Acylo- 
'brachia, Gray 1848 ; Apygia, Testicardines, Lineicardines and Denti- 
<'ardines, Bronn 1862; Articulata, Huxley 1864; ('listenterata, King 
.1873. 
