554 BRITISH PAL/EOZOIC FOSSILS. [CepHALopopa. 
BELLEROPHON Larcomi (Portk.) 
Ref.—Portk. Geol. Rep. t. 29. f. 13. (reduced one half linear). 
Desc.—Globose ; subhemispherical; casts of about two very rapidly enlarging whorls, entirely exposed in 
the umbilicus, which is extremely deep, from the rapid enlargement of the whorls; edge of the umbilicus 
obtusely angulated, steeply sloped, slightly convex, and excavated along the middle; periphery very broadly 
rounded without any distinct ridges or furrows; mouth moderately dilated, bilobed at the outer edge, and 
with a short angular sinus in the middle; shell extremely thick; callus on inner lip, very large, flattened, 
smooth. Surface imperfectly seen, but apparently without distinct keel, marked with obscure, moderately 
arched sulci or ridges of growth, and apparently a small, open umbilicus. Width of nearly adult specimen 
85 40 
at mouth six inches, proportional diameter ;5, antero-posterior diameter of mouth =, diameter of umbilicus 7 
1009 100° 
Diameter of casts before the abrupt dilatation of the mouth three and half inches, proportional width of 
such imperfect specimens *,, or nearly equal to the diameter; diameter of umbilicus =, antero-posterior 
diameter of mouth *. Width of small old specimen, with external shell, at mouth five inches three lines, 
proportional antero-posterior diameter of entire shell =; antero-posterior diameter of dilated mouth ;;. 
This is by far the largest species of Bellerophon known. The shell is extremely thick (considerably upwards 
of an inch at the sides of mouth in old specimens). In general characters small specimens much resemble 
the B. apertus; but instead of two-thirds of the inner whorls being concealed by the outer ones, when looking 
directly into the umbilicus of casts, they are entirely exposed, though not to such an extent as in B. cornu- 
arietis, the casts of which, by their remarkably slender, widely separated whorls, have no resemblance whatever 
to the B. Larcomi. The present species differs both from the B. apertus and B. cornu-arietis in the extreme 
width of the whorls compared with their diameter, and the very rapid increase of the whorls in size, causing 
their remarkably steep-sided, obtuse, angular-edged umbilicus. The periphery is very broadly rounded, most 
prominent in the middle, and without any distinct ridges or sulci either on the outer surface or internal casts. 
Position and Locality —Not uncommon in the impure carboniferous limestone of Kendal; one small slightly 
narrower specimen, possibly of this species, in the collection from Lowick. 
BELLEROPHON PHILLIPst. 
An apparently smooth species, probably the B. apertus of Phillips, occurs abundantly in the state of casts 
at Kendal, and more rarely at Dent and Lowick. The casts much resemble those of the true B. apertus and B. 
costatus, but having the proportional width of the umbilicus ;;, as compared with the diameter; being therefore 
intermediate between those species: if distinct from any known form when perfect exteriors are found, it might 
be called B. Phillips. 
BELLEROPHON RECTICOSTATUS (Po7rth.) 
Ref.—Portk. Geol. Rep, t. 35. f. 5. 
Two casts, too obscure for description, one from Lowick and one from Kendal, probably belong to this 
species, as they agree with B. apertus in the proportional width of the umbilicus (7;), but differ in being 
100. 
marked with two large spiral sulci coinciding with the band, and one or two fainter ones on each side. 
BELLEROPHON TANGENTIALIS (Phiil.) 
Ref-—Phill. Geol. York. Vol. II. t. 17. f. 6, 7, and 4. 
Desc.—Globose ; periphery broadly rounded, slighty flattened; umbilicus wide, deep, rounded, with very 
tumid sides; keel forming a single, strong, prominent, narrow ridge. Surface crossed by strong, irregular, 
subimbricated ridges, separated by wide flat spaces; transverse ridges usually joining the keel at right angles, 
