338 MOLLUSCA. TORNATELLADiE. Bellerophon. 
“ Shell glossy, white, veined like ivory in a longitudinal direction, and 
furnished with eight or nine reversed volutions, slightly tapering to an ob- 
tuse point ; the lower whorl occupies two-thirds of the shell ; the aperture 
is narrow, not quite half the length of the shell ; and the columella possesses 
one plication. Length a quarter of an inch 5 breadth one-third of its length.”^ 
Mont . — This species, in all probability, is likewise the type of a new genus. 
Gen. BELLEROPHON. — Shell spiral, involute, the last 
whorl enclosing the others ; aperture arched, extremities 
simple, with a sinus in the middle of the outer lip. 
* With a mesial hand. 
1. B. hiulcus — Globose, expanded ; closely striated, the striae sharp, ele- 
vated, passing obliquely from the mesial band, which is flat, broad, with its 
sides defined by sharp depressed lines ; a central cavity on each side. — Conchy, 
liolithus Nautilites hiulcus. Mart. Pet. Derb. t. xl. f. 2 — Bel. hiulcus, Sower. 
IVIin. Conch, t. cccclxx. f. 1 . — Carboniferous limestone., Derbyshire. 
2. B. tenuifascia — Spherical, with a well defined central cavity, finely stria- 
ted ; mesial band linear, elevated. — Conch. Naut. hiulcus, var. c. Mart. Pet. 
Derb. p. 15. — B- ten. Sower. Min. Conch, t. cccclxx. f. 2, 3, — Carboniferous 
limestone., Derbyshire and Yorkshire. 
3. B. costatus. — Globose, expanded, subcarinated, with slender sharp ribs 
diverging from the undefined broad convex band ; with a central cavity — 
Conch. N. hiulcus. Mart. p. 15, t. xl. f. 1. Parh. Or. Bern. iii. 141. t. x. f. 6, 
7 — B. cost. Sower. Min. Conch, t. cccclxx. f. 4 — Carboniferous limestone., Der- 
byshire. 
4. B. decussatus . — Shell somewhat ovate longitudinally, with numerous 
spiral ridges, crossed by finer ones, giving the points of union a subtubercu- 
lar aspect ; mesial band rounded, longitudinally striated, decussated by the 
transverse fine ridges, which in crossing have a concave bend. — In my cabi- 
net from slate-clay of the coal formation., Linlithgowshire. 
5. B. striatus — Longitudinally ovate ; with numerous, fine, slightly rough, 
spiral ridges : mesial band slightly flattened, and longitudinally striated. 
This species differs from the last in the mesial band being more elevated, 
and in the nearly total absence of the transverse ridges. In one specimen 
there is a thick inner lip spreading on the surface of the last whorl. — From 
the same -place as the last. 
** Destitute of a mesial band. 
6. 1^. apertus . — Nearly spherical ; sides of the aperture expanded; shell 
smooth, tliick ; with a well defined central cavity — Sower. Min. Conch. 
t. cccclxix. f. 1 In Carboniferous Limestone., Lowth. I have a specimen from 
carboniferous limestone in Linlithgowshire, agreeing in form with one pre- 
sented to me by Mr Wright from Lowth. 
7. B. corrm-arietis Elongated ; sides of the aperture expanded ; shell very 
thick, smooth, faintly marked by the lines of growth. The shell, when a little 
corroded, becomes coarse and laminated — ^Nautilus, Ure., Hist. Ruth. 308. 
t. xiv. f. 8. — B. corn. Sower. Min. Conch, t. cccclxix. f. 2. — Mr Sowerby’s 
specimens are from Limestone^ Kendal ; mine are from Carboniferous Limestone^ 
Linlithgowshire. 
8. B. Urii Globular ; sides of the aperture expanded ; shell smooth, re- 
gularly sulcated spirally ; the furrows shallow, the ridges rounded, '-Nauti» 
