84 
Is'AUTILOIDEA. 
with epidermids, representing the surface of the mantle of the 
mollusc. 
Remarhs. This species is distinguished from its congeners by its 
small size, and by the ribs which ornament the surface. 
Horizon. Etage E (= Salopian). 
Locality. Lochkow, Bohemia. 
Fairly well represented in the Collection. 
DEVONIAN SPECIES. 
Barrandeoceras orienS) Hall, sp. 
1876. or/ews, Hall, Illustrations of Devonian Fossils : Cepha- 
lopoda, pi. Ixi. f. 1. 
1879. Nautilus oriens, Hall, Nat. Hist, of New York, Palteontology, 
vol. V. pt. ii. p. 420, pi. Ixi., pi. cv. f. 2, pi. cvi. f. 8. 
1879. Cf. Nautilus maximus (Conrad), Hall, ibid. p. 418, pis. Ixiii., 
Ixiv. 
Sp. Char. ‘‘ Shell large, subovoid, discoid, making about three 
volutions, which are slightly re-entrant [overlapping]. Umbilicus 
very wide, exposing all the volutions. Transverse section subcir- 
cular. Tube somewhat gradually enlarging in the inner volutions. 
The apical angle, as taken from a compressed specimen, is about 
15°. 
“ Chamber of habitation large, ventricose, rapidly expanding. 
Aperture opening at right angles to the axis of the tube, with a 
gentle sinus on each side of the convex ventral face of the shell. 
Air-chambers regular, deep, increasing in depth with the enlarge- 
ment of the volutions. The measurements of two specimens give a 
depth of twenty to twenty-five mm. 
“ Septa regular, distant, having a greater concavity than the 
depth of the air-chambers, strongly imbricating. As measured on 
the ventrum of one specimen, they have a distance of twenty-five mm., 
where the tube has a diameter of seventy- five mm. Suture lines 
strongly marked on the casts and partial casts of the interior. 
“Test imperfectly preserved, and its thickness not determined. 
Ill the compressed and macerated specimens, partially retaining the 
shell, or its impressions upon the cast, the surface is shown to have 
been marked by fine, lamellose, somewhat undulating striae of 
growth, and finer elevated lines, which are interrupted by coarser 
revolving striae, and these are especially conspicuous on the dorsal 
side, on the margins, and within the cavity of the umbilicus, form- 
ing low rounded ridges, which are at unequal distances. Similar, 
