310 BRITISH PALAZOZOIC FOSSILS. [CepHALopopa. 
wide furrows (traces of thickening of lip); sometimes obscure traces of coarse obsolete spiral furrows; from 
this size the mouth rapidly expands. Adult (B. expansus): (small specimen) length six lines; in proportion to 
length, length of mouth 5, width of mouth double its length; spire small, globose, inrolled ; umbilicus small ; 
mouth large, transversely elliptical, bilobed by a wide V-shaped sinus; surface with obscure, lateral wrinkles, 
arching from the umbilicus towards the middle of the outer surface parallel with the double lobe of the outer 
lip. 
In old specimens one inch long there is a long narrow slit about nine lines in length and less than half a 
line wide, continued from the apex of the V-shaped sinus of the outer lip, which retains the form of the above 
description. There can, I think, be not the slightest doubt of the propriety of uniting the Bellerophon globatus 
and the B. expansus of Sowerby ; the excellent figure of the former given in the Silurian System, corresponding 
exactly with specimens before me, shews traces on the side, of the concentric wrinkles; it is the largest size 
before the rapid expansion of the mouth begins; the rather small figure of the latter species (equally good) 
shews the greater number of the lateral wrinkles developed and the form of the perfect mouth; and between 
these I have traced all the gradations. The surface is unknown, but several of the casts shew a spiral sulcation 
similar on a small scale to that of the B. dilatatus. 
Position and Locality—Common in the Upper Ludlow rock of Underbarrow, and Benson Knot, Kendal, 
Westmoreland ; tilestone of, Horeb Chapel, Llandovery, S. Wales; Upper Bala schists of  Dolydd Ceiriog 
Waterfall, E. of the Berwyn Mountains ; Upper Ludlow rock, near Ludlow, Shropshire. 
BELLEROPHON Murcuisontr (d’O70.) 
Ref. and Syn.=B. striatus (Sow. not of Bronn) Sil. Syst. t. 3. f. 12¢. 
Sp. Ch.—Inyolute, subcompressed, of about one and half very rapidly enlarging, completely exposed 
whorls ; section of whorls obtusely cordate, the width slightly exceeding the length; sides tumid, very convex ; 
circumference with an obtusely-defined, broad, prominent, flattened keel; umbilicus small; surface with fine, 
sharp strive, transverse on the sides and keel; average diameter five lines; in proportion to diameter, length of 
mouth =, width of umbilicus 4%. 
The greater width and tumidity of the sides, fewer and more rapidly expanding whorls, and consequently 
greater size of the last volution, and wide obtusely-flattened keel, separate this species from the B. cari- 
natus (Sow.) 
Position and Locality.—In the tilestone of Horeb Chapel, Llandovery, S. Wales. 
BELLEROPHON ORNATUS (Conrad Sp.) 
Syn. and Ref. = Cyrtolites ornatus Id. Geol. Rep.; Hall, Pal. New York, t. 84. f. 1. 
Sp. Ch.—(Spire exposed, of two and half or three volutions, Hall) ; whorls with a strong rounded keel ; 
section subrhombic; sides marked with thick, prominent plaits, extending from the edge of the umbilicus 
nearly to the base of the keel, with a slight backward curvature; the intervening spaces are wide and concave, 
(a fragment of last whorl, with a diameter of four lines, is three lines wide, and the summits of the lateral plaits 
are one line apart). 
The portions preserved of this species agree with the American specimens figured by Hall, in which the 
diameter of the perfect shell is nine lines, and the proportional diameter of the mouth 5. Under a strong lens 
our specimens shew some traces of the minute net-like striation of the surface. 
Position and Locality—Not uncommon in the dark Bala limestone of Teirw river, S. of Llangollen, 
N. Wales. 
