64 MOLLUSCA. 



Genus XXIV CANCELLARIA — Lamarck. 



Plelrotoma. 



inner lip broadly reflected on the columella above, and nar- 

 rowing as it descends, provided willi two plaits, and a spiral 

 Shell oval, subturreted; spire short in most species, nJge; outer lip a little thickened near the edge, and ribbed 

 but produced in a few; body large, ventricose, greatly internally. 



exceeding the spire in length ; aperture not quite entire. Found in the London Clay at Highgate, Barton, and Lynd- 



the base being for the most part somewhat extended into hurst. 

 a canal, distinct in some cases, but always short and re- 

 curved ; outer lip transversely sulcated within ; inner lip 

 reflected over tlie columella, and part of the front of the 

 body; columella plaited, varying in number and size, for 

 the most part they are large, compressed, and much de- 

 pressed, in some instances they are small, few, and placed 

 far within the columella, so as to be nearly obscured ; at 

 other times low down. 



1. C. QUADDATA The Squarc-shapcd CanccUaria, pi. 



XXXVI. fig. 41, 42. 



Cancellaria quadrata. Sowerby, Min. Conch. IV. p. 83, pi. 



360. Fleming, Urit. An. p. 334. 



Oblong-ovate ; spire of medium length, consisting of four 

 inflated volutions, the body occupying about two-thirds the 

 length of the shell, separated by a narrow suture, and termi- 

 nating in a rather obtuse apex; whole shell provided with sharp, 

 elevated, spiral, longitudinal, and very regular stria?, the spiral 

 ones the strongest ; the intermediate spaces being small, 

 hollow squares; aperture oblique, oblong-ovate, contracted both 

 above and below ; inner lip broadly spread over the columella, 

 on which there are two obtuse plaits, with a spiral fold on its 

 cdce ; outer lip sharp, entire, internally striated. 



Perfect sf)ecimens of this shell are to be met witli, varying in size 

 from three-eighths of an inch to nearly an inch and a quarter. 



Found in the London Clay at Barton. 



2. C. EVL'LSA. — The Drawn-out Cancellaria, pi. XXXVI. 

 fig. 46, 47. 



Cancellaria ev^iUa. Sowerbv, Min. Conch. IV. p. 84, pi. 



361, fig. 2, 3, 4. Fleming, Brit. An. p. 334. Succinum evul- 

 sum, Brander, Foss. Hant. p. 13, pi. 1, fig. 14. 



Shell ovate, short; body large; spire short, consisting of five 

 narrow, subturreted volutions, terminating in an acute apex ; 

 provided with varicose, longitudinal varices and ribs, crossed by 

 many elevated, spiral striae, which are most prominent as they 

 pass over the ribs and varices, with intermediate, less prominent 

 stria;, producing a roughness to the touch ; aperture oblique, 

 oblong-ovate, contracted both above and below ; pillar lip 

 broadly reflected on the columella, the base of which is pro- 

 vided with two strong plaits and a spiral ridge, beneath which 

 is a very short, rounded canal ; outer lip sharp at the edge, 

 with a strong varix behind, and striated internally. 



Found abundantly at Barton in the London Clay, as also at 

 Lyndhurst, Southamptonshire. 



3. C. L.EViuscuLA.— The Smoothish Cancellaria, pi. XXX\'I. 

 fig. 39, 40. 



Cancellaria Iceviusctila. Sowerby, Min. Concli. IV. p. 84, 

 pi. 361, fig. 1. Fleming, Brit. An. p. 334. 



Shell short ; body large ; spire small, consisting of four in- 

 flated volutions, well separated by the suture, and terminating 

 in an acute apex ; provided with longitudinal somewhat waved 

 varicose varices and ribs, crossed by numerous, obtuse, elevated 

 stria: ; aperture oblique, rounded above, and contracted beneath ; 



Genus XXV— PLEUROTOMA.— /.a/«a/-cA. 



Shell fusiform, turreted ; spire generally longer than 

 the body ; aperture oval, with a canal more or less 

 elongated at its base ; outer lip with a notch or fissure 

 at the upper part, contiguous to the suture; operculum 

 horny, accuminated, its nucleus situate at the lower 

 extremity ; some of the species are covered by a thin 

 epidermis. 



1. P. COLON. — The Colon-marked Pleurotoma, pi. 

 XXXVII. fig. 10. 



Pleurotoma colon. Sowerby, Min. Conch. II. p. 106, pi. 

 146, fig. 7, 8. Fleming, Brit. An. p. 355. 



Fusiform ; body and spire nearly of equal length ; the latter 

 consisting of six or seven subturreted volutions, terminating in 

 an acute apex, these are concave above, with their margins cre- 

 nulated, and deeply divided by the suture; below the projecting 

 margin, the body and volutions of the spire are provided with 

 numerous, rugged, spiral ridges, alternating, with fine stria;, 

 which in some specimens divide the undulations into two small 

 tubercles, crossed by many short longitudinal undulations, which 

 are frequently doubled in the same manner as the undulations ; 

 base conical; aperture oblong-ovate, nearly half the length of 

 the shell, ending in an obtuse beak ; diameter about a third of 

 its length. 



Found in the London Clay at Barton Cliff. 



2. P. SEMICOLON.— The Semicolon-marked Pleurotoma, 

 pi. XXXVIL fig. 5. 



Pleurotoma nemicolon. Sowerby, Min. Conch. II. p. 106, 

 pi. 146, fig. 6. Fleming, Brit. An. p. 355. 



Elongated, turreted ; body and spire nearly equal in length ; 

 spire consisting of four or five inflated volutions, provided witli 

 granuated margins, which correspond with the long, narrow, 

 curved spiral ribs ; base of body conical, decussated ; aperture 

 ovote, one-third the length of the shell, ending in a nearly 

 straight canal, which is a little expanding below ; outer lip thin 

 on the edge ; pillar lip smooth, slightly reflected on the colu- 

 mella. 



Found in the London Clay at Slubbington. 



3. P. COMMA The Comma-marked Pleurotoma, pi. 



XXXVIL fig. 8, 9. 



Pleurotoma comma. Sowerby, Min. Conch. II. p. 105, pi. 

 246, fig. 5. Fleming, Brit. An. p. 355. 



Elongated, turreted; body somewhat shorter than the spire, 

 consisting of five or six volutions, which, as well as the 

 body are smooth in the middle, with numerous short, curved, 

 elevated, longitudinal ribs on their superior portion, these are 

 most prominent above, and pointed below in the form of com- 

 mas ; furnished with a few acute, elevated, sharp spiral stria;, 



