CEPHALOPODA. 405 
Messrs. Meek and Hayden described N. eccentricus, from the Permian system 
{Trans. Albany Institute, vol. 4). 
In 1859 Mr. Billings described N. Jason , N. natator and N. tyrans, from the 
Chazy limestone {Canadian Naturalist and Geologist). 
In 1860 J. Hall described N. biserialis, from the Coal Measures of Iowa 
{Geolog. Surv. of Iowa, supplement to vol. 1, pt. 2) ; Lituites capax [^iV. capax] 
and N. occidentalis (not N. occidental's, Swallow, 1858), from the Niagara group 
{Geolog. Surv. of Wisconsin: Rep. of Prog.); N. {Discites) ornatus [— N. Marcel- 
lensis ], Gyroceras liratum [= Nautilus liratus ] and Gyroceras expansum, var. Saem. sp. 
[= Nautilus], from the Hamilton group {Thirteenth Rep. N. Y. State Cab. Nat. Hist.). 
Messrs. Meek and Worthen described N.- Chesterensis, N. spectabilis and N. 
subglobosus (the latter since referred to N. globatus, Sow.), from the Carbonif¬ 
erous limestone ; N. {Discus) digonus, from the Kinderhook group; N. {D.) 
planorbiformis and N. {D.) Sangamonensis, from the Coal Measures {Proc. Acad. 
Nat. Sci. Phila.). 
Mr. J. H McChesney described N. Forbesianus, N. lllinoisensis, N. quadrangulus 
and N. nodocarinatus, from the Coal Measures; and Cyrtoceras giganteum [ =Nau- 
tilus], from the Niagara group {New Palaeozoic Fossils).* 
Prof. G. C. Swallow described N. Gilpini, from the Coal Measures, and N. 
Lawsi, from the Hamilton group {Trans. St. Louis Acad. Sci.). 
In 1861 Mr. McChesney published Lituites cancellatus [=i\ r . cancellatus], from 
the Niagara group (compare with Lituites=Nautilus capax). 
Messrs. Meek and Worthen described Nautilus {Trematodiscus) trisulcatus. 
In 1862 Mr. A. Winchell described N. ingentior, Trematodiscus altidorsatis, 
T. discoidalis, T. Meekanus, T. planidorsatis, T. striatulus, T. strigatus and T. trigo- 
nus, from the Marshall group {Amer. Jour. Sci., 2d series). 
In 1865 Mr. Billings described N. calciferus, N. ferox and N. Pomponius, from 
the Calciferous group; N. desertus, N. versutus and N. insolens, from the Quebec 
group {Palaeozoic Fossils). 
* In a revision of this paper by Mr. F. B. Meek, in 1869, he makes the following synonomy: Nautilus 
occidentalis, Swallow, 1858, =N. quadrangulus, McC., 1S60,=IV. nodocarinatus, McC.,=ZV. biserialis, Hall, 
1860. It is also to be remarked that these species are closely related to, if not identical with, [IV.] Discites 
tub&'culatus, Owen, 1852 (not N. tuberculatus, Sowekbv, 1821). 
