274 EOCENE MOLLUSCA. 
are covered by numerous very fine, closely set lines, either perfectly simple or feebly 
decussated by the longitudinal lines; and again, others in which the longitudinal 
lines are almost obsolete. 
Size.—Axis, 1 inch; diameter, 4-12ths of an inch. 
Localities. —Barton, Highcliff. 
No. 198. Pxrevrotoma conirera. Ff. 2. Edwards. Tab. XXXI, fig. 3, a, 6. 
P. testa angustd, elongato-fusiforii, sub-turrita, undique spiraliter lineata: spird 
elevatd, acuminata: anfractibus ad humeros sub-angulatis, in juventa tuberculatis, deinde 
angusta teniold cinctis ; postice leviter cavatis, marginatis ; antice planulatis, sub-conicis ; 
ultimo anfractu in canalem latum, mediocriter longum, reflecum producto ; lineis spiralibus 
elevatis, filiformibus, confertis, sepe irregularibus: apertura sub-quadratd ; labro ad 
humerum sinuato; sinu latiusculo, profundo, sub-trigono; columella contortd, antice 
cristata. 
Shell narrow, elongated, fusiform, sub-turreted, and ornamented with concentric 
raised lines; the spire pointed, elevated, rather exceeding the aperture in length ; 
the whorls, seven or eight, exclusive of a small, smooth, sharply conical pullus of 
three volutions, are slightly channelled along the posterior margins, bluntly angulated 
at the shoulders, flatly convex at the sides, and tapering gradually towards the base ; 
in the young state they present at the angle a row of small, vertical tubercles, but this 
ornament is lost on the third or fourth whorl, and is thence replaced by a narrow, 
smooth, ribbon-like band; the posterior margins are thickened round the sutural 
edge, which is crenulated and bordered by two spiral lines more prominent than the 
other marginal lines. The last whorl is produced in front into a long, wide canal, 
curved by the columella, and having the anterior extremity slightly bent backwards ; 
the flattened sides and tapering form of the whorls impart to the spire the appearance 
of a succession of inverted cones, gradually diminishing in size, each being half con- 
cealed by the succeeding one. The elevated spiral lines are numerous and thread- 
like ; sometimes they are regular and equal in size, but more frequently a very fine line 
intervenes between two thicker lines ; and they are generally roughened by the prominent 
lines of growth. ‘The aperture is sub-quadrate; the outer lip but little arched, thin, 
sharp-edged, and smooth within; the sinus is placed on the shoulder and is deep, 
rather narrow, and triangular in form; the columella is slightly twisted, and at the 
anterior extremity presents a small crest caused by the reflexion of the canal. 
The present species appears to be well-marked; I do not know of any other 
Pleurotoma resembling it in the peculiar form of the spire, or in the elegant con- 
centric lineation which adorns it. It is rare. 
Size.—Axis, 10-12ths of an inch; diameter, 3-12ths of an inch. 
Localities.— Bracklesham Bay, Bramshaw. 
