Ammonita. MOLLUSCA. CEPHALOPODA. ^41 
ing in a carinated margin ; aperture cordate. — In limestone of the Upper 
Oolite^ at Shotover, Oxfordshire. 
4. A. quadrata — Depressed, whorls 4 or 5, the inner ones half concealed ; 
surface with projecting, furcate, undulating radii, extending into a creriated 
margin ; aperture obtusely square.— ;S'owcn Min. Conch, t. xvii. f. 3. — In a 
gravel-pit, Suffolk. 
5. A. serrata — Depressed, whorls 5, the inner ones two-thirds concealed ; 
surface radiated and undulated near the circumference, keel distinct, nearly 
cylindrical, with a concavity in the shell on each side, sharply crenated, con- 
taining the siphunculus ; apertures narrow, five-angled. — Sower. Min. Conch, 
xxiv — At AVorlinghame. 
G. A. Mantelli — Depressed, whorls 3 or 4, two-thirds concealed, edge three 
sided, broad and flattish ; sides flattish, ridges alternately entire, and extend- 
ing only about two-thirds across the whorl ; the outer edges of the partitions 
have five principal folds ; aperture obscurely six-sided — Sower. Min. Conch, 
t. Iv.— In Chalk Marl, Ringmer, Sussex. 
7. A . planicosta Depressed, v/horls 6, exposed, with transverse, obtuse 
ribs, flattened in front ; mouth circular, slightly indented by the preceding 
whorl Sower. Min. Conch, t. Ixxiii. — In Chalk Marl, and Lias ? 
8. A. jugosa. — Depressed, keeled, whorls 4, half concealed, with regular, 
straight, transverse, obtuse ribs ; aperture ovate, narrowest at the front.— 
Sower. Min. Conch, f. xcii. £ 1. — In the Inferior Oolite, Ilminster. 
9. A. triplicata . — Whorls 4, exposed, ribs twice curved, alternately one 
long and three short ; a smooth line along the front ; aperture obovate. — Sower. 
Min. Conch, t. xcii. f. 2 — Upper Oolite, Portland Isle. 
10. K.elliptica. — Depressed, keeled, inner whorls two-thirds exposed; ridges 
broad, slightly curved, few, and obscure near the margin ; aperture acutely 
elliptical ; keel sharp — Sower. Min. Conch, t. xcii. f. 4. — In Lias, Char- 
mouth. 
11. A. stellaris — Depressed, with a groove on each side of an obtuse keel ; 
whorls four, flattish on the sides, about two-thirds exposed ; ribs numerous, 
straight, two of which cross each partition ; syphon in the keel ; aperture 
longer than wide. Surface with obscure, distant, decussating strise. — Sower. 
Min. Conch, t. xciii — In Lias at Lime. 
12. A. Depressed, acutely keeled, whorls 3, the inner ones two- 
thirds concealed ; ribs numerous, equal, twice curved ; keel distinct, entire, 
aperture acutely triangular, the^ inner angles truncate. — Sower. Min. Conch, 
t. xciv. upper figure . — Inferior Oolite, Ilminster. 
13. A. concava. — Depressed, keeled, whorls 4, two-thirds concealed, a large 
central cavity, ribs numerous, curved, unequal in length, obsolete near the 
centre ; keel sharp, entire ; aperture acutely triangular, external angle round- 
ed, internal angles obliquely truncate — Sovjer. Min. Conch, t. xciv. lowest 
figure . — Inferior Oolite, Ilminster. A. t. clxvi. this species is said to occur 
likewise in the Middle Oolite at Dry Sandford, Berkshire. 
14. A. splendens Depressed, front flat, with crenulated edges; whorls 3, 
quickly diminishing, three-fourths concealed ; sides flat ; ribs alternately 
long and short; aperture long, narrow in front — Sower. Min. Conch, t. 103. 
— Chalk Marl, Folkestone. 
15. A. Callmicensis Depressed, subumbilicate ; whorls 5, three-fourths con- 
cealed ; front flat, ribs small, numerous, alternately one long and from two 
to five short ; aperture orbicular when young, deltoid, with the angles trun- 
cated when old — Sower. Min. Conch, t. 104 . — Middle Oolite, Kellaways 
Bridge- 
VOL. I. 
Q 
