~~ 
CrpHatopopa. | LOWER PALASOZOIC MOLLUSCA. 3821 
shire, and near Aymestry, Herefordshire; one specimen from the Upper Ludlow rock of Brigsteer, Kendal, 
Westmoreland. 
Explanation of Figwres—P1. 1. L, fig. 31, natural size; 31a, portion of surface magnified to shew the 
fine longitudinal strize crossing the rings. 
OrTHOCERAS (Cycloceras) TRACHEALE (Sow. Sp.) 
Ref. and Syn. = Orthoceras Sow. id. Sil. Syst. t. 3. f. 9b = Orthoceras perelegans Salt. Mem. Geol. Surv. Vol. IT. 
Part 1. t. 13. f. 2 and 3. 
Sp. Ch.—Shell long, nearly cylindrical, with occasional abrupt diminutions in diameter, girt with obtusely- 
rounded, slightly oblique rings, one line in diameter, and four in the space of half an inch, with a diameter of 
four to seven lines; about four rings in a space of three lines, at a diameter of three lines; interannular spaces 
concave, a little wider than the rings; surface girt with very fine, subequal, rough, transverse strize, about 
eleven in the space of one line ; septa one between each ring. 
This species to the naked eye is scarcely distinguishable from the O. (Cycloceras) Ibex, the rings are how- 
ever thicker and more obtuse, and as about the same number occurs in a given space, they are proportionally 
closer together than in that species, from which it is perfectly distinguished by the minute striation being 
transverse instead of longitudinal. Sowerby’s figure (having the shade on the side which is lightest in the other 
figure) represents a hollow cast of the exterior, giving the rings a deceptive appearance of being wider than 
the interspaces. 
Position and Locality—Upper Ludlow rock of Kirkby Moor, Kendal; tilestone, Storm Hill; Upper 
Ludlow of Benson Knot, Kendal, Westmoreland; near Ludlow? Shropshire; olive schists of Dinas Bran, 
Llangollen, Denbighshire ; flags of the Wenlock shale, Howgill Fell, near Sedbergh, Kendal, Westmoreland. 
Subgenus. POTERIOCERAS (M/°Coy). 1844. 
Ref. and Syn. = Gomphoceras (Sow. not of Thunberg), = Bolboceras Fisch. (not of Leach), 
= Apioceras (Fisch.) 1844. 
Gen. Char.—Shell short, fusiform, section circular, mouth contracted; septa simple; siphon subcentral, 
moniliform. 
Fischer's genus has nearly as early a date of publication as mine, but as the latter has been used in many 
works I continue to use it. 
OrTHOCERAS (Poterioceras) ELLIPTICUM (A/‘Coy). 
Syn. and Ref. < Orthoceras pyriforme Sow. Sil. Syst. t. 8. f. 19. (lower and not upper figs.) and f. 20. 
Poterioceras ellipticum M°Coy, Ann. Nat. Hist. 2nd Series, Vol. VII. p. 45. 
Sp. Ch.—Wlliptical, last chamber conoidal; greatest width at last septum, from whence the chambered 
and unchambered portions taper elliptically to the contracted mouth and attenuated extremity ; septa nearly 
horizontal, the last three or four about two lines and half apart: greatest width of last chamber (at septum) 
two inches three lines, length of last chamber two inches four and half lines. 
There are clearly two species confounded by Sowerby in the Sil. Syst. under the name Orthoceras pyri- 
forme; the difference in form he supposed to be produced by the direction of pressure, but I find it to be 
constant in perfectly uncrushed specimens. To that represented by his upper figure I would restrict his 
specific name pyriforme, its characteristic pear-shaped form being mainly owing to the greatest width being 
in the middle of the last chamber or midway between the last septum and the mouth, the upper half of the 
last chamber being abruptly rounded, while the other portion of the shell tapers gradually ; while in the other 
species the greatest width is at about the last one or two septa, from whence the last chamber tapers gradually 
to the mouth at about the same curve that the chambered portion tapers towards the apex, giving a very 
different regularly elliptical figure to the present species, which I have named accordingly. 
Position and Locality—Common in the Lower Ludlow rock, near Aymestry, Herefordshire. 
[rasc, 11.] ANY 
