Orthocera. MOLLUSCA. CEPHALOPODA. 239 
** Striated transversely, 
10. O. striata — Nearly cylindrical, septa numerous, deep ; syphon nearly 
central ; surface regularly striated transversely. — Smer. Min. Conch, t. Iviii. 
Flem. Wern. Mem. iii. 96. — Transitimi Limestone^ Cork. In the clay-slate of 
the same formation, at the Cove of Cork, another species occurs, the charac* 
ters of which are not established. 
1 1. O. Steinhaueri — Tapering ; chambers deep, partitions distant, even 
edged, circular ; syphon close to one side ; striae of the surface regular and 
even. — Sower. Min. Conch, lx. f. 4. — In Carboniferous Limestone. 
12. O. gigantea. — Shell gradually tapering, finely striated, aperture up- 
wards of 8 inches in diameter ; septa direct, numerous, deep ; syphon a small 
distance from the centre — Sower. Min. Conch, t. ccxlvi. — In limestone of 
the Old Red Sandstone^ Dumfriesshire. 
Surface with transverse ridges. 
13. O. sulcata — Shell tapering ; ridges waved and striated ; syphon small, 
central. The length of one specimen is 2 inches and ,®oths, diameter at 
the base at the apex y®oths. It contains thirty-one ridges, which 
are twice waved in going round the shell : both the ridges and intervening 
grooves are finely striated. — Ure‘*s Ruth. 306, t. xvi. f. 2. Flem. An. Phil. v. 
202, t. xxxi. 6 — In slate-clay of the Coal Formation. 
14. O. undata. — Shell tapering, ridges waved and smooth ; pipe small, cen- 
tral. In a specimen 1 inch and in length, it is ,’oths in diameter at 
the base, and upwards of at the apex ; with eleven ridges, more deep- 
ly waved, and less numerous than the preceding. There is the appearance 
of an epidermis of a black colour, and obscurely striated ; where the shell is 
exposed, both the ridges and the grooves are perfectly smooth. An imper- 
fect specimen of an Eschara adheres to the shell. — Flem. An. Phil. v. 203.— 
In slate-clay of the Coal Formation. 
15. O. Subcylindrical ; ridges distant, nearly even and smooth. 
The largest portion of the shell which I possess is about I inch in length, 
and upwards of /oths in diameter ; ridges nearly |th distant ; more obtuse 
than the preceding, with at least two chambers in the interval— F/m. Ann. 
Phil. V. 203.— In Carboniferous Limestone. 
16. O. annulata — Tapering, subcompressed, with strong, waved, slightly 
oblique ridges, and intervening striae : syphon sublateral ; a space near the 
aperture without ridges.— iS'oecer. Min. Con. t. cxxxiii— Cariwii/crows Lime- 
stone^ Colebrookedale. 
17. O. rwyosa— Subcylindrical ; ridges waved, and tuberculated with longi- 
tudinal lines ; syphon minute, and placed close to the edge. The length of a 
specimen which I possess is IJ inch ; the diameter i®oths; the ridges are 
asunder, and contain two chambers in the interval — Flem. Ann. Phil. v. 203. 
—In Carboniferous Limestone, 
mm W'ith longitudinal planes or furrows. 
18. O. Gesneri Conical, with numerous longitudinal furrows, regularly 
concave and close,— Mar<. Pet. Derb. t. 38. f, 1, 2. — In Carboniferous Lime^ 
stone, Derbyshire. 
17. O. angularis.-^'N early cylindrical, angular, with about 16 smooth lon- 
gitudinal planes ; syphon small and lateral. I possess about half an inch of 
this shell, which is nearly of equal thickness, scarcely exceeding the tenth of 
an inch in diameter. — Flem. Ann. Phil. v. 203. t. xv. f. 10. — In Carboniferous 
Limestone. 
