NAUTILID^. 
91 
1847. Nautilus discors, d’Orbigny, Paleontologie Uniyerselle, \ol. i. 
pi. xci. ff. 1, 2. 
1849. Nautilus discors, d’Orbigny, Prodr. de Paleout, Statigr. yol. i. 
p. 110. 
1852. Nautilus discors, Giebel, Fauna der Yorwelt, Band iii. Abtb. i. 
p. 177. 
1854. Nautilus discors, Morris, Cat. of British Foss. p. 308. 
1860. Discites discors, Griffith, Journ. Geol. Soc. Dublin, yol. ix. p. 56. 
1878. Nautilus discors, de Koninck, Faune du Calcaire Carbonifere de 
la Belgique (Annales du Mus. Boy. d’Hist. Nat. de Belgique, 
tom. ii.), pt. i. p. 143, pi. xxx. ff. 8 a, 8 b. 
1883. Discitoceras discors, Hyatt, “ Genera of Fossil Cephalopods,” 
Proc. Boston Soc. Nat. Hist. yol. xxii. p. 292. 
Char. “ Discoid, compressed, yrhorls five, entirely exposed 
[only just in contact], quadrate, back conyex, equal in -width to the 
sides exclusiye of the umbilical slope, sides slightly flattened, cyenly 
conyex ; surface of the yoiing shell (and inner whorls of the old) 
marked with strong longitudinal (spiral) sulci, crossed by yery 
fine strife : last yolution of adult specimens marked with coarse 
transverse sigmoidal strife only. 
“ I have named this species from the remarkable difference in 
striation between the young and old volutions, which is so great 
that they might be taken for different species ; it resembles the 
A. suhsulcatvs, Phill., most nearly, but is distinguished by the cha- 
racter of the striation, and by not having, at any period of growth, 
either the two keels on the back, the keel on the sides, or any con- 
cavity on the latter, the sides being regularly convex, and the back 
broader in proportion to the width of the sides . . . (M'-Coij.) 
Remarhs. M‘Coy’s accurate description leaves nothing to be added 
to the diagnosis of this species. 
Horizon. Carboniferous Limestone. 
Loadity. Naas, near Dublin. 
Bepresented in the Collection by a single example. 
Discites compressus^ J. Sowerby, sp. 
1813. JEllipsolitcs co77ij)rcsst<s, J. Sowerby, Min. Conch, yol. i. p. 84, 
pi. xxxyiii. 
1844. Nautilus (Discites) mutahilis, M‘Coy, S^mop. Carboniferous Foss. 
Ireland, p. 18, pi. iii. f. 7. 
1847. Nautilus midabilis, d’Orbigny, Paleont. Universelle, yol. i. 
pi. Ixxxviii. ff. 1-4. 
1849. Naidilus mutahilis, d’Orbigny, Prodr. de Paleont. Stratigr. yol. i. 
p. 110. 
1852. Nautilus mutahilis, Giebel, Fauna der Vorwelt, Band iii. Abth.i. 
p. 178. 
