3UG 
NAUTILOIDEA, 
1858. NauliliLs De Kayi, Tuomej, Second Biennial Report on the Geo- 
logy of Alabama (Appendix No. 2), p. 259. 
1860. Nautilus Dekayi, Conrad, Joiirn. Acad. Nat. Sci. Philadelphia, 
vol. iv. new series, p. 276. 
1876. Nautilus Dekayi, Meek, Report of the United States Geological 
Survey of the Territories, vol. ix. p. 496, woodcut, f. 67, pi. xxvii. 
ff. 1, a-e. 
[_Not 1857. Nautilus Dekayi, Shiimard, Trans. Acad. Sci. St. Louis, 
p. 124 {Jide Whiteaves '). — 1859. Nautilus Dekayi, Binkhor.st, 
Esquisse Geologique et Pal4ontologique des Couches CrcStac^s du 
Limbourg, pp. 8, 38, 40, 53, 67,91, 146, 169. — 1862. Nautilus 
Dekayi, Coquand, G^ologie et Pal^ontologie de la region sud de 
la Province de Constantine, p. 305. — 1866. Nautilus Dekayi, Bel- 
tremieux, Faune Fossile du Departement de la Charente-In- 
f^rieure, p. 80.— 1868. Nautilus Dekayi, Dewalque, I'rodrome 
d’une Description Geologique de la Belgique, ]>p. 358, 397. — 
1869. Nautilus Dekayi, Favre, I)escri])tion des Mollusques Fos- 
siles de la Craie des Environs de Lemberg en Galicie, p. 7, pi. iii. 
ff.^3. — 1879. Nautilus Dekayi, Ubaghs, Description Geologique 
et Paleontologique du Limbtiurg, p. 201. — 1881. Nautilus Dekayi, 
Mourlon, Geologie de la Belgique, vol. ii. p. 101.] 
Sp. Char. “ Shell subglobose, broadly rounded on the periphery 
and sides ; umbilicus closed ; volutions increasing rapidly in size, 
or more than doubling their diameter each turn, about half as wide 
again as high, all hidden but the last or outer one ; aperture much 
wider than long, transversely reniform, the lateral extremities being 
rounded, and the inner side deeply sinuous for the reception of the 
inner whorls ; lip having a wide shallow sinus along the peripheral 
side, prominently rounded on the lateral margins, and again sinuous 
near each umbilicus ; septa moderately concave, and about sixteen 
or eighteen to each turn : siphuncle small, located one fourth to \ 
one third of the distance across toward the periphery, from the j 
margin of the inner side ; surface of adult or medium-sized specimens j 
nearly smooth, or having very obscure lines of growth, crossed by j 
faint traces of longitudinal striae; on young individuals, or the j 
' inner volutions of larger ones, these lines are quite distinct in both j 
directions, and form a very neat, cancellated style of ornamentation ; j 
internal casts sometimes showing a slender longitudinal line on the ■ 
centre of the periphery. 
“ The proportions are shown by the following measurements of a j 
young individual : — Length 1 ‘84 inches ; breadth of aperture !• 70 | 
inches ; diameter of aperture in the direction of the length or 
^ Geol. Surv. Canada, Mesozoic Foss. (1879), vol. i. pt. ii. p. 09. 
