90 
NAUTILOIDEA. 
Localities. British. Kildare ; Kaas, near Dublin. — Foreign. Yisc, 
Belgium. 
Well represented in the Collection by several fine specimens. 
Discites discus, J. Sowerby, sp. 
1812. Nautilus discus^ J. Sowerby, Min. Conch, vol. i. p. 39, pi. xiii. 
1854. Nautilus (Discites) discus, Morris, Cat. Brit. Foss. p. 308. 
1855. Nautilus (Discites) discus, M‘Coy, British Pal. Foss. fasc. iii. 
p. 558. 
1878. Nautilus difficilis, de Koninck, Faune du Calcaire Carbouifere de 
la Belgique (Annales du Mus. Boy. d’Hist. Nat. de Belgique, 
tom. ii.), pt. i. p. 118, pi. xxvi. f. o. 
/Sp. Char. Depressed, edge flat, aperture oblong, volutions not 
concealed by each other. 
“ About four inches in diameter ; greatest thickness or width of 
the aperture half an inch. Turns of the spire about five. Chambers 
very numerous. Septa distant from each other about one-eighth of 
an inch. Outer edge of the aperture narrower than the inner one, 
notched, owing to a small groove which runs round the outer edge 
[periphery] of the shell. Siphuncle nearer to the inner edge of the 
septa.” (Sowerhy.) 
llemarlcs. This species is closely allied to the Nautilus (Discites) 
trochlea of M‘Coy, which, however, differs, as M‘Coy has pointed 
out, in having a “ much shorter and wider mouth, and smaller and 
deeper umbilicus, and the consequent much greater thickness, or 
less lateral compression, in proportion to the diameter” \ 
I can find nothing by which to separate the present species from 
N. difficilis, de Koninck, which is merely a young example of our 
shell • but being a more complete specimen, it gives the proportions 
of the shell more accurately than can be gathered from the type 
specimen, which is not so perfect. Sowerby has restored it in his 
figure. 
Horizon. Carboniferous Limestone. 
Locality. Kendal, Westmorland. 
Represented in the Collection by the type specimen, which is 
contained in the “ Sowerby Collection.” 
Discites discors, M‘Coy. 
1844. Nautilus (Discites) discors, M‘Coy, Synop. Carboniferous Foss. 
Ireland, p. 17, pi. iii. f. 5. 
^ British Palgeozoic Fossils, fasc. iii. p. 561, pi. 3ii. f. 16. 
