TURRITELLA. 



MOLLUSCA. 



69 



The shell is smooth, except where the sharp carinse 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. Concli. 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 strife ; 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._TURBINACEA. 



Shell turreted, or conical, with an oblong or rounded 

 aperture, not expanding, and the margin disunited. 



Genus XXIX.— TURRITELLA— iaraarc^. 



Shell turreted; spire greatly elongated, consisting of 

 many volutions ; body small in proportion to the spire ; 

 aperture orbicular or subaugulated, 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. 1, 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 Highgate; 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 sidcata. 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. 



XXX vin. 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 striae, more remote towards the middle of the volu- 

 tions, and when viewed through a lens, presents a regularly 

 crenulated appearance, and with fine intermediate striae. 



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 strife. Length one inch. 



Found in the London Clay at Barton Cliff, Hampshire. 



6. T. INCKASSATA The Thickened Turritella, pi. 



XXXVIH. 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 

 striae, 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 



