Pleurotoma. 
MOLLUSCA. 
65 
which are most prominent near the middle of the volutions ; 
aperture oblong-ovate, about two-fifths the length of the shell, 
terminating in a short, slightly curved canal. 
Found in the London Clay at Stubbington. 
4. P. acuminata —The Acuminated Pleurotoma, pi. 
XXXVII. fig. 6. 
Pleurotoma acuminata. Sowerby, Min. Conch. II. p. 105, 
pi. 146, fig. 4. Fleming, Brit. An. p. 355. 
Shell greatly elongated; body considerably shorter than the 
spire, which consists of nine or ten turreted, inflated volutions, 
which are concave above, provided with a fimbriated margin, 
and terminating in an acute apex, the volutions being separated 
by an elevated thread-like suture; the whole shell with many 
longitudinal, slightly waved ribs, which are thickest and more 
elevated above, on the body, and sulcato-striated below; many 
spiral, fine striae invest the shell from the apex to the base; 
aperture oblong-ovate, which, including the beak, is one-fifth 
the length of the shell, and ending in a wide canal. 
Found in the London Clay at Ilighgate Hill. 
5. P. exorta. — The Risen Pleurotoma, pi. XXXVII. 
fig. 2. 
Pleurotoma exorta . Sowerby, Min. Conch. II. p. 104, pi. 
146, fig. 2. Fleming, Brit. An. p. 354. Murex exortus , 
Blander, Foss. Ilant. p. 20, pi. 2, fig. 32. 
Elongated, turreted ; base conical; spire and body of nearly 
equal length; spire consisting of nine or ten inflated volutions, 
which are concave and smooth above, convex below, with twelve 
or fourteen longitudinal, undulated costae, which arc most pro¬ 
minent on the spire; the smooth and concave portion of the 
volutions is bounded by the abrupt commencement of the ribs, 
with many tuberculated, spiral lines; length of aperture and 
beak equal to two-fifths of the length of the shell, and elon¬ 
gated in form, ending in a slightly curved, short canal; outer 
lip thin; inner lip slightly reflected on the columella. 
Found in the London Clay at Barton Cliff. 
6 . P. rostuata. —The Beaked Pleurotoma, pi. XXXVII. 
fig. 11. 
Pleurotoma rostrata. Sowerby, Min. Conch. II. p. 104, pi. 
146, fig. 3. Fleming, Brit. An. p. 354. Murex rostratus, 
Brander, Foss. Ilant. p. 21, pi. 2, fig. 34. 
Shell fusiform ; body and spire of nearly equal length ; spire 
consisting of eight or nine expanded, convex volutions, slightly 
concave above, somewhat ventricose and rough below, and 
separated by a wide suture, granulated in the centre; upper 
part of the body, and ventricose portion of the volutions of the 
spire, provided with short, broad, rather obscure, longitudinal 
ribs; the whole shell crossed by numerous spiral ridges, and 
narrow, elevated, sharp, somewhat undulating ribs, which feel 
rough to the touch by means of the lines of growth ; the whole 
surface obscurely decussated, but more distinct towards the edge ; 
aperture ovate, ending in a long, narrow, and nearly straight 
canal. 
Found in the London Clay at Barton Clift', Hampshire, and 
at Devizes. 
7. P. attenuata. —The Slender Pleurotoma, pi. XXXVII. 
fig. i. 
Pleurotoma attenuata. Sowerby, Min. Conch. II. p. 103, 
pi. 146, fig. 1. Fleming, Brit. An. p. 354. 
Fusiform; body a little longer thsn the spire; base attenu¬ 
ated ; spire consisting of nine greatly produced volutions, a 
little flattened above, deeply separated by the suture, and each 
provided with a series of projecting, blunted, wide-set tuber¬ 
cles ; body with five or six longitudinal, undulating costae, 
crossed by numerous, transverse, sharp, subtuberculated, nar¬ 
row’, undulous ribs, with many intermediate and fine striae; 
aperture elongated, narrow, which with the beak is about equal 
to half the entire length of the shell; beak tapering gradually 
from the upper portion of the body; the longitudinal, irregular 
lines of growth make the shell feel rough to the touch. Dia¬ 
meter of the shell about one-fourth its length. 
Found in the London Clay at Stubbington. 
8. P. rrevirostra.—T he Short-beaked Pleurotoma, pi. 
XXXVII. fig. 3, 4. 
Pleurotoma brevirostrum. Sowerby, Min. Conch. IV. p. 
120, pi. 387, fig* 2. Fleming, Brit. An. p. 355. 
Elongated, turreted; body short; spire long, consisting of 
ten or eleven ventricose, abruptly tapering volutions, flattened 
at top, separated by a deep suture, and terminating in an acute 
apex; lower parts of volutions of the spire, and upper portion 
of the body, with many elevated, longitudinal ribs; whole shell 
crossed by numerous spiral striae, which are strongest upon the 
middle of each volution; aperture obovatc, ending in a short, 
slightly curved narrow canal; outer lip thin ; inner lip smooth, 
broadly reflected on the columella. 
Found in the London Clay at Muddiford. 
9. P. fusiformis _The Spindle-shaped Pleurotoma, pi. 
XXXVII. fig. 14. 
Pleurotoma fusiformis. Sowerby, Min. Conch. IV. p. 119, 
pi. 387, fig. 1. Fleming, Brit. An. p. 355. 
Elongated, fusiform; body long; spire short, consisting of 
seven abruptly tapering volutions, slightly flattened above, and 
subcarinated, separated by a striated, and elevated smoothish 
fillet, their lower portions furnished with eight or nine longitu¬ 
dinal, somewhat obscure, depressed ribs; whole shell with deep 
spiral striae, and also with longitudinal striae, which is arcuated 
near the top of the volutions, and following the sinus in the 
upper part of the outer lip; aperture oblong, lanceolate, widest 
above, and narrowing as it descends, terminating in a widish 
canal; beak not well defined ; outer lip rather thick; inner lip 
reflected on the columella, and transversely Striated. This 
shell feels rough to the touch, from the elevated lines of growth 
and decussating stria?. 
Found in the London Clay at Ilighgate Hill. 
10. P. priscuS _The Ancient Pleurotoma, pi. XXXVII. 
fig. 12, 13. 
Pleurotoma prisons. Sowerby, Min. Conch. IV. p. 119> pi. 
386. Fleming, Brit. An. p. 355. Pleurotoma clavicular is, 
Lamarck, Env. de Paris, p. 69- Hist. Nat. An. San. Vert. 
VII. p. 98. Murex priscus , Brander, Foss. Hunt. p. 16, pi. 1, 
fig. 25, and pi. 3, fig. 44. 
Fusiform, turreted, smooth; base of body transversely sul- 
cated; body and spire of about equal length; spire consisting 
of eight slightly convex volutions, terminating in a sharp apex ; 
the volutions separated by a flat suture, on which arc two or 
three wide spiral stria?; base of shell considerably produced, but 
destitute of a distinct beak, blunt at the lower extremity, and 
R 
