530 BRITISH PALALOZOIC FOSSILS, [GasrErRopopa. 
PLEUROTOMARIA SUBMONILIFERA (D’Orb.) 
Ref. and Syn. = P. monilifera Phill. Geol. York. Vol. II. t. 15. f. 10 @ (not of Zieten), = P. submonilifera 
d Orb. Prodrome, p. 128. 
Desc.—Conical, globose ; spire of about seven rapidly increasing whorls; apical angle 75°; band strong, 
deeply hollowed, bounded by two strong prominent keels placed a little above the middle of the body-whorl, 
the lower one touching the deeply-channelled suture on those of the spire; a strong sulcus below the lower 
keel on the body-whorl; base very convex; umbilicus small, rounded; whorls above the prominent band 
flattened, marked with two, or rarely three, strong spiral, equidistant rows of granules, the upper one coinciding 
with the edge of the suture; base covered below the band on body-whorl with very numerous, close, subequal, 
obtuse, granulated strize ; fine oblique strize cross the spiral lines on the base, and rather more distant and 
stronger ones arch from the suture to the band on the upper part of the whorls. Average length three 
lines, width about the same or slightly more, proportional height of last whorl 2, of penultimate whorl 4. 
Position and Locality—Common in the mountain-limestone of Derbyshire ; not uncommon in the car- 
boniferous shales of Glasgow. 
PLEUROTOMARIA UNDULATA (Phill.) 
Ref—Phill. Geol. York. Vol. IT. t. 15. f. 14, 
Dese.—Globose, spire very small, obtuse, of four and half whorls; apical angle about 107°; band very 
broad, flat, very prominent, bounded by narrow vertical sides, situated on the middle or most prominent part 
of the body-whorl, and its lower edge corresponding with the suture on the spiral whorls, of which it nearly 
equals half the width; about twice its width from the upper suture of the body-whorl. Surface with extremely 
coarse transyerse plicee, about their thickness apart, semicircularly arched on the band, arching slightly back- 
wards to the keel on the upper part of the whorls, and nearly direct on the base of the body-whorl after a 
slight curve near the band ; between each of the plicze are two or three fine irregular lines; whorls tumid 
above the band; base of the body-whorl very tumid, rounded; umbilicus very small, rounded ; mouth rounded. 
Average width two lines, proportional length about #4, height of last whorl about , height of penultimate 
whorl about ;4; width of band one-third of a line. 
This very strongly-marked species cannot be confounded with any other, from the great width and promi- 
nence of its band, and the coarseness of its sculpturing. The very small size of the species renders the propor- 
tional measurements rather uncertain. 
Position and Locality—Not uncommon in the lower carboniferous limestone of Isle of Man. 
PLEUROTOMARIA YVANNI (L’Eveillé Sp.) 
Ref. and Syn.=Trochus Yeoanni VEveillé, Mém. de la Soc. Geol. de France, Vol. II. t. 2. f. 24. = Pleuroto- 
maria concentrica Phill. Geol. York. Vol. Il. t. 15. f. 23; $+ Buccinum parallele id. ib. t. 16. f. 8; $+ 
Pleurotomaria canaliculata M°Coy, Synop. t. 6. f.38; P. Yeannide Kon. Anim. Foss. Bel. t. 37. f. 1 and 7. 
Desc.—Conical, spire of six to seven whorls; apical angle varying from 60° to 85°; band coinciding with 
an angulation of the whorls, which is a little nearer to the upper than the lower suture; the space above this 
angulation flat or slightly concave, sloping at an angle of 45° in the long varieties, becoming more nearly hori- 
zontal in the short varieties. Surface below the angulation nearly vertical or parallel to the axis of the shell, 
flat or very slightly convex ; base of body-whorl tumid, rounded; umbilicus small, conical, almost obsolete in 
the very long varieties; surface marked with coarse, subequal, spiral strize (three to four in two lines on body- 
whorl at nine lines in diameter), those above the angulation much finer than those below it, usually four to five 
below the angulation, and five or six finer ones above it on the spiral whorls; band scarcely distinguishable 
from the other sulci between the pairs of ridges; surface, when finely preserved, crossed by minute oblique 
