CrpHALopopa. ] LOWER PALA®OZOIC MOLLUSGCA. 313 
developed within the siphon. Cameroceras (Conrad) is according to Hall an Orthoceras, inclosing a young shell 
which was mistaken for a lateral siphon. 
ORTHOCERAS ANGULATUM ( Wahi.) 
Ref. and Syn.—His. Leth. Suec. t. 10. f. 1 = Orthoceras virgatum Sow. Sil. Syst. t. 9. f. 4. 
Sp. Ch.—Conical, about six inches long, tapering at the rate of two and half lines in one inch, from a 
diameter of nine lines, at which size the surface has about twenty-eight narrow, prominent, longitudinal ridges, 
separated by wide concave spaces, faintly and minutely striated transversely, (strize twenty-eight in one line), 
and varying from two-thirds to one and quarter lines in width; section broad-oval ; siphon eccentric towards 
the upper end; septa scarcely oblique, about one and half lines apart. 
The transverse strie are six to seven times more in a given space than in the O. calamitewm (Miinst.), 
which induces me to leave in this species as a provisional variety (8), a fragment from the black shale of Builth 
Bridge, and another from the shale of Llangynyw, in which obscure indications of transverse annuli appear 
at the distance of those in that species, but which may be produced by the resistance of the edges of the 
septa to the crushing. 
Position and Locality—Common in the Upper Ludlow rock of Brigsteer, and Underbarrow, Kendal, 
Westmoreland; Lower Ludlow mudstone, Garden Quarry, Aymestry, Herefordshire ; mudstone (Wenlock 
shale) of Llangynyw Rectory, near Welchpool, Montgomeryshire ; black Upper Bala shale of Builth Bridge. 
ORTHOCERAS BACULIFORME (Salt.) Pl. 1. L. fig. 27. 
ef.—Salter, in Appendix. 
Sp. Ch.—Very elongate, conic, tapering at the rate of two-thirds of a line in one inch; section oval ; 
siphon moderate, subcentral ; septa gently convex, direct, with a slight backward wave on each side; a dozen 
septa at a diameter of six to seven lines, uniformly two lines apart. 
A specimen four inches long, of which two inches three lines is unchambered, seems only to taper one and 
half lines, the commencement of the chambered portion being slightly narrowed and very slightly expanding 
towards the mouth; the surface cannot be seen, the only preserved portion being covered by a parasitic coral. 
Position and Locality —Rare in the Upper Ludlow rock of Brigsteer, Kendal, Westmoreland. 
Explanation of Figures—P| 1. L. fig. 27, natural size of fragment; 27a, end view, shewing form of 
section and position of siphon. 
OrTHOCERAS Bricuti (Sow.) 
Ref.—Sil. Syst. t. 12. f. 21. 
Sp. Ch.—Tapering at the rate of two lines in one inch, from a diameter of one inch six lines; siphon very 
large, cylindrical, subcentral, having at the above diameter of the tube a diameter of four lines, and marked by 
slightly oblique constrictions, about four lines apart, from each of which an irregular lamellar extension forms a 
ring within the siphon about a line wide. 
The fragment I have examined does not shew the internal structure of the siphon fully, nor is any trace 
visible of the external surface of the tube or septa, the form of the tube being defined by a mass of calcareous 
Spar. 
Position and Locality.—Common in the Wenlock limestone of Ledbury, Herefordshire. 
ORTHOCERAS BULLATUM (Sow.) 
Ref —1d. Sil. Syst. t. 5. f. 29. O. striatum Id. id. p. 612, not of Min. Con. = Orthoceratites substriatus 
D’Orb. Prod. 
Sp. Ch.—Section broad-oval, tapering at the rate of three lines in two inches, from a diameter of one 
inch five lines, and haying at that diameter the six or seven last septa about one and half lines apart and 
[rasc. 11] Ss 
