Turritella. 
MOLLUSCA. 69 
The shell is smooth, except where the sharp Carinas appear: its 
length being only about half an inch, and its diameter half its 
length. 
Found in the Lower Fresh Water formation, Isle of Wight. 
12. P. ventricosus. —The Bellied Potamis, pi. XXXVII. 
fig. 25. 
Potamides ventricosus . Sowerby, Min. Conch. IV. p. 53, 
pi. 341, fig. 1. Potamidum ventricosum , Fleming, Brit. An. 
p. 358. 
Shell conical, turreted, body a third of its length; spire 
consisting of nine or ten ventricose, longitudinally ribbed, and 
sprirally striated, deeply divided volutions, each with two or 
three strong striae, which nearly divide the ribs into three 
tubercles; base convex, with two additional striae; aperture 
orbicular, destitute of an internal furrow on its upper part, and 
terminating below in a very short, slightly curved canal; outer 
lip but little twisted, and even on the edge; inner lip somewhat 
reflected on the columella, and smooth. 
Found in the Fresh Water formation at Cowes, Isle of 
Wight. 
SECTION II.—PHYTIPHAGA. 
Shell with the aperture entire, and destitute of a 
notch or canal. 
FAMILY I_TURBIN ACE A. 
Shell turreted, or conical, with an oblong or rounded 
aperture, not expanding, and the margin disunited. 
Genus XXIX.—TURRITELLA.— Lamarck . 
Shell turreted; spire greatly elongated, consisting of 
many volutions; body small in proportion to the spire; 
aperture orbicular or subangulated, entire, its margin 
disunited above, but not reflected; outer and inner lips 
thin, with a slight sinus, situated generally near the 
upper part, well marked in some species; a more or less 
distinct sinus at the inferior and inner part of the lip, 
which is here very slightly reflected, but not turned back; 
aperture furnished with a horny operculum. 
1 . T. conoidea. —The Conical Turritella, pi. XXXVIII. 
fig. 23. 
Turritella conoidea. Sowerby, Min. Conch. I. p. 109? pi. 
51, fig. I, 4, 5. Fleming, Brit. An. p. 304. 
Shell greatly elongated, taper; body occupying about a fourth 
of the length; spire very long, consisting of sixteen or seven¬ 
teen almost flat-sided volutions, slightly projecting over each 
other at their base, and separated by an angular spiral groove; 
whole shell beset with regular spiral striae, seven or more on 
each volution, with intermediate minute ones, all of which are 
acutely crenulated ; aperture nearly circular, slightly contracted 
above; outer lip plain, simple; no reflection of the inner lip 
upon the columella. 
Found in the London Clay at Ilighgate; also at Stubbington, 
and in the Crag at Holywell. 
2. T. Edita.— The Produced Turritella, pi. XXXVIII. 
fig. 21. 
Turritella edita. Sowerby, Min. Conch. I. p. Ill, pi. 51, 
fig. 7. Fleming, Brit. An. p. 304. Turbo editus , Brander, pi. 
3, fig. 48. 
Shell greatly elongated; body somewhat more than a fourth 
the length of the shell; spire very long, consisting of eighteen 
or nineteen deeply divided volutions, somewhat flattened on the 
sides, the lower parts ventricose, with numerous nearly obsolete 
spiral striae; aperture circular; outer lip plain. 
Found in the London Clay. 
3. T. sulcata. —The Furrowed Turritella, pi. XXXVIII. 
fig. 10. 
Melania sulcata. Sowerby, Min. Conch. I. p. 85, pi. 39? 
middle fig. Fleming, Brit. An. p. 317. 
Shell rather strong, much elongated; body very short, little 
more than a seventh of the whole; spire very long, consisting 
of sixteen or seventeen ventricose, spirally striated volutions, 
separated by a well defined, deep, concave sulcus, and having a 
marginated ridge along the superior portions of the volutions. 
Found in the London Clay at Stubbington Cliffs. 
4. T. elongata. — The Lengthened Turritella, pi. 
XXXVIII. fig. 1. 
Turritella elongata. Sowerby, Min. Conch. I. p. 110, pi. 
51, fig. 2. Fleming, Brit. An. p. 304. 
Shell greatly elongated; body nearly a third of the total 
length; spire consisting of thirteen or fourteen lengthened 
volutions, separated by a well defined suture, the base of each 
volution projecting beyond that below it, upper portion of the 
volutions somewhat rounded, flattened in the middle, the lower 
portion rather angular and projecting; whole shell covered with 
numerous stria?, more remote towards the middle of the volu¬ 
tions, and when viewed through a lens, presents a regularly 
crenulated appearance, and with fine intermediate stria?. 
Found in the London Clay at Barton Cliff, and Christchurch, 
Hampshire. 
5. T. brevis. —The Short Turritella, pi. XXXVIII. fig. 3. 
Turritella brevis. Sowerby, Min. Conch. I. p. 110, pi. 51, 
fig. 3. Fleming, Brit. An. p. 304. 
Shell elongated, body equal to a third of its length; spire 
consisting of nine or ten well defined volutions, their superior 
and lower margins equally rounded, and furnished with ten or 
twelve spiral, finely crenulated stria?. Length one inch. 
Found in the London Clay at Barton Cliff, Hampshire. 
6. T. incrassata. — The Thickened Turritella, pi. 
XXXVIII. fig. 28. 
Turritella incrassata. Sowerby, Min. Conch. I. p. Ill, pi. 
51, fig. 6. Fleming, Brit. An. p. 304. 
Shell strong, greatly elongated; body not quite a third of its 
total length; spire consisting of about fourteen volutions, with 
flattened sides, their lower parts angular, terminating in an acute 
apex, with three elevated, nearly equidistant, smooth, spiral 
stria?, the two lower ones more elevated than the superior one, 
that in the centre being the most prominent; opposite to 
which, on the outer lip, in full grown shells, it is provided with 
an internal eminence, which produces a thickness in the outer 
lip in its centre; inner lip reflected on the columella, behind 
s 
