DESCRIPTION OF THE FOSSILS. 
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B. decussatus, Flem. PI. XVII. fig. ]3, Kulkeagh ; Linlithgowshire. 
Globular, aperture very much expanded, axis solid, band tumid ; shell covered by 
small spiral ridges and furrows, crossed by transverse sharp threads forming scales or 
elevated points on the ridges. 
B. apertus. Sow. PI. XVII. fig. 4. Fermanagh; Carlingford ; Kirby 
Lonsdale ; Bristol. 
Nearly spherical, (without a band?) inner whorls concealed in the shell, (apparent 
in the cast) axis solid and very thick ; sides of the aperture expanded. 
B. cornu arietis. Sow. PI. XVII. fig. 16. Kendal; Northumberland. 
Whorls few, rapidly enlarging from a rather compressed to a very much expanded 
section ; aperture expanded on the sides, with a deep acute dorsal sinus. Shell very 
thick. 
B. Urii? Flem. PI. XVII. fig. 11, 12. Bowes; Bolland ; Harelaw ; 
Linlithgowshire. ? 
Globular, aperture very expanded, axis solid, no hand, smooth, many regular spiral 
furrows, the intermediate ridges narrow, rounded. The cast of the interior smooth. In 
respect of shape it seems to differ from Dr. Fleming’s description. 
B. spiralis. Ph. PI. XVII. fig. 8. Bowes ; Harelaw, and Otterbum. 
Ovate, umbilicate, back and edges of the umbilicus obtuse-angled. Many spiral 
furrows and ridges, surface very minutely granular. (Cast smooth.) 
B. Woodwardii. (Nautilus Woodwardii, Sow.) PI. XVII. fig. 1, 2, 3. 
Bolland ; Kulkeagh ; Derbyshire. 
Lenticular, whorls few, subrhomboidal, partly involute ; a dorsal sulcus, and many 
spiral beaded lines. In old shells the lines are nearly plain striae, and the inner whorls 
are more concealed, 
CEPHALOPODA POLY TLIAL AMI A, 
The following species though referred to Nautilus, a genus of. ex- 
isting mollusca, really belong to several genera most of them extinct. 
Nautilus dorsalis. Ph. PI. XVII. fig. 17- Pi. XVIII. fig. 1, 2. 
Spire rapidly augmenting, so as to leave a large very deep umbilicus ; siphuncle 
dorsal ; septa distinct. There are two if not three varieties of this same general form, 
all with dorsal siphuncle. a. has a rounded umbilicus and inner whorls partly con- 
cealed, (Bolland.) /3. has an angular umbilicus, whorls more involute, (Bolland.) 
7 , less involute, umbilicus open, rounded, (Kildare.) 
N. endosiphonus. Ph. Coal shale of Halifax. 
Aperture quadrangular, narrowing toward the flat back, Iunulate on the inner 
side ; siphuncle very near the inner edge. 
