216 PERMIAN FOSSILS. 
unusually produced, and the upper half of the whorls flattened, as exampled in the 
specimen represented by fig. 6, Pl. XVII; in these respects it agrees very closely 
with Dr. Geinitz’s Pleurotomaria Verneuili : the specimen of the latter represented in the 
‘ Verstemerungen,’ pl. iii, fig. 18 a, 6, c, however, appears to have a wider umbilicus. 
My largest specimen is five eighths of an inch in height axially. 
Pleurotomaria antrina is rather common in some places; for example, Tunstall Hill, and 
Silksworth, in Shell-limestone ; but somewhat rare at Humbleton Quarry, Castle Eden- 
Dene, and Dalton-le-Dale, in the same rock; and extremely rare at Tynemouth-Castle 
Chiff in the Breccia. According to Dr. Geinitz, it occurs in the Zechstein-dolomite at 
Gliicksbrunn and Konitz; and according to Credner, near Asbach and Schmalkalden. 
PLEUROTOMARIA TUNSTALLENSIS, (ing. Plate XVII, figs. 3, 4, 5. 
PLEUROTOMARIA TUNSTALLENSIS, King. Catalogue, p. 14, 1848. 
Diagnosis.—Conical. Whorls evenly rounded; marked with fine spiral lines, and 
slight incremental striz. Aperture sub-orbicular: with the pillar-lip oblique. Fissure 
deep, and situated in the medio-longitudinal part of the whorls. 
This species resembles the last in form; but it is non-umbilicated, and its pillar-lip 
is oblique: it is also related to Pleurotomaria striata, J. Sow.; but instead of the 
umbilicus being closed by a somewhat thick and a rather broad callosity, which is the 
case with the latter, according to De Koninck, it is without any callosity, and its 
pular-lip is sharp, though a little reflexed. The apical whorls are occasionally trans- 
versely plicated near the suture ; as displayed in the enlarged representation at fig. 5, 
Pl. XVII. 
Although this and the preceding shell have been specifically separated, I have 
considerable doubts as to their really being distinct,—or, perhaps, it would be better 
to say, that I feel considerable difficulty in separating them: whether this is owing to 
there being no specific difference between them, or to their closely simulating each 
other, I am certainly not much disposed to contend for: if, however, it be necessary 
to unite them, it will almost be impossible, from their various modifications, to draw 
up any other than a very general diagnosis of the species. My largest specimen 
measures a quarter of an inch in its axial length. 
Pleurotomaria Tunstallensis occurs at Tunstall Hill in Shell-limestone; but not so 
often as the last species. 
PLEUROTOMARIA NODULOSA, Avng. Plate XVIL, fig. 9. 
PLEUROTOMARIA NoDULOSA, King. De Verneuil, Bull. Soc. Géol. de France, 2™ série, 
vol. i, p. 35, 1844. 
— — » Geol. Russ., vol. i, p. 225, 1845. 
— — Tennant, Strat. List, p. 89, 1847. 
—- -— » King, Catalogue, p. 14, 1848. 
= os » Howse, Trans. T, N. F. C., vol. i, p. 238, 1848. 
