Cbenatula. MOLLUSCA. PERNAD^. 391 
2. G ? acMiftz.— Ovate lanceolate, oblique, narrow, depressed, slightly cur- 
ved; anterior extremity acute; teeth in the hinge variously disposed. — 
Sower. Min. Conch, t. dx. £ 5. — In Calcareous Sandstone^ at CoUyweston. 
3. G. avkuloides. — Obliquely ovato-lanceolate, curved; both extremities 
pointed ; hinge-line nearly half the length of the shell ; hinge-teeth few. — 
Sower. Min. Conch, t. Ixi. and t. Dlxvi.— -In Green and Oolite. 
Gen. CRENATULA. — Shell subequivalve, depressed ; hinge 
with numerous pits, without teeth for the reception of the 
ligament. 
1. C. Ovate, elongated, ventricoso-carinated ; posterior side 
impressed ; beaks pointed. — Sower. Min. Conch, t. ccccxliii ? 
2. C. Listeri. — List. Conch, t. cccclxvii. f. 34-6.— -Park. Org. Rem. iii. 220. 
t. XV. f. 5. — Upper Oolite. 
3. C. producta. — Park. Org. Rem. iii. 221. t. xv. f. 6, 7.—“ la ^ Marl-pit 
near Sbefford, in Bedfordshire.” 
Gen. INOCERAMUS.— Shell inequilateral, irregular ; hinge 
a marginal, subcylindrical, transversely sulcated callus, sup- 
porting a ligament ; beaks conspicuous at one end of the 
hinge. 
1. I. Cuvieri — Obovate, curved, convex, with transverse, distant, obtuse 
waves ; posterior side concave, with a small lobe near the heak.— Sower. 
Linn. Trans, xiii. 457* — Mant. Suss. 213. t. xxvii, £ 4. t. xxviii. £ 1-4 — Ca- 
tillus Cuvieri, Cuvier., Oss. Foss. ii. 251. t. iv. £ 10 Sower. Min. Conch. 
t. ccccxli. £ 1.— In Chalky 
2. I. Brongniarti. — Oblong, gibbose, with large transverse undulations ; 
anterior side angular, lobed ; posterior side flat, truncated and smooth ; beaks 
small, curved, and pointed. — Mant. Suss. 214. t. xxvii. £ 8. — Sower. Min. 
Conch, t. ccccxli. £ 2, 3 In Chalk. 
3. I. mytiloides. — Equivalved, elongated, depressed, with slight irregular 
waves ; convex and obtuse towards the beaks ; hinge-line oblique ; anterior 
side produced ; beaks short — Mant. Suss. 215. t. xxviii. £ 2.— -Sower. Min. 
Conch, t. ccccxlii. — In Chalk. 
4. I. cordiformis — Equivalved, heart-shaped, transversely and interrupted- 
ly waved ; beaks large, incurved ; anterior side angular. — Sower. Min. Conch, 
t. ccccxl. — In Chalk. 
5. I. concentricus. — Unequivalved, ovate, one of the beaks much produced, 
incurved.— -(Park. Geol. Trans, v. 58. t. i. £ 4.) — Sower. Min. Conch, t. cccv. 
— In Chalk Marl. 
6. I. sulcatus — Unequivalved, oblong, Avith prominent beaks, and about 
nine large longitudinal plaits; beak of one valve, incurved, acute.— (Park. 
Geol. Trans, v. 59. t. i. £ 5.)— Sower. Min. Conch, t. cccvi.— In Chalk Marl. 
7- I. Lamarkii — Valves equal, very convex, with a few obscure longitudi- 
nal undulations, and distant transverse ridges ; surface covered with nume- 
rous concentric striae ; posterior slope subdepressed; anterior side lobate, ex- 
panded; hinge nearly transverse (Park. Geol. Trans, v. 55.) Mant. 
Suss. 214. t. xxvii. £ 1 In Chalk. 
