370 MOLLUSCA. ACEPHALA. Terebratula. 



subcarinated ; lesser valve convex — Sewer. Min. Conch, t. c. ; upper figure — 

 In Green Sand. 



11. T. lata Orbicular, depressed ; beak prominent ; larger valve subcari- 

 nated at the back Sower. Min. Conch, t. xc ; lower figure — In Green Sand. 



12. T. ornilhocephala — Ovato-rhomboidal ; depressed when young; elon- 

 gated and gibbous when old ; front straight, bounded by two obtuse lateral 

 depressions, similar in each valve — Soiver. Min. Conch, t. ci. f. 1, 2, 4 — In 



Lias. 



13. T. lampas Ovato-rhomboidal gibbous ; front straight, produced, lesser 



valve depressed. — Sower. Min. Conch, t. ci. f. 3 — In Has, at Lyme. 



14. T. obovata Obovate, transverse, gibbous, flatfish; beak prominent; 



front straightish, bounded by two obsolete plaits — Sower. Min. Conch, t. ci. 

 f. 5. — In Lias. 



15. T. retorquata. — Oblong, ovate, front depressed by a large rounded plait ; 

 sides elevated, rounded ; lower valve obtusely carinated, with a sharp beak, 

 and a longitudinal ridge along each side — T. resupinata, Soiver. Min. Conch, 

 t. cl. f. "£\.— Inferior^ Oolite. 



1G. T. coarctata. — Subheptagonal, gibbose, hispid, and decussated ; lesser 

 valve convex, subtrilobated ; larger valve biplicated, with a deep angular 

 sulcus between the plaits. — Park. Org. Rem. iii. 229. t. xvi. fl 5. Sower. Min. 

 Conch. 312. f. 1, 4 — Oolite. 



17. reticulata. — Obovate, gibbose, subhispid, decussated; front obscurely 

 three-sided ; lesser valve convex ; larger valve obtusely biplicated, with a 

 shallow channel between the ridges. — Sower. Min. Conch, t. cccxii. — Oolite. 



18. T. acuminata. — Heart-shaped ; front much elevated, with a deep acute 

 angular sinus in the margin ; surface finely striated — Mart. Derb. t. xxxii, 

 xxxiii. f. 5, 8. Sower. Min. Conch, t. ccexxiv. and t. ccccxcv.— In Carboni- 

 ferous Limestone. 



19. T.affinis. — Orbicular, strongly striated ; upper valve gibbose, with an 

 elevated sinus in the front ; lower valve nearly flat.— Soiver. Min. Conch. 

 t. ccexxiv. f. 2 — In Carboniferous Limestone. 



20. T. resupinata.— Transversely ovate, longitudinally striated ; striae mi- 

 nute, numerous, and equal ; imperforate valve most convex ; perforation tri- 

 angular — Mart. Derb. t. xlix. f. 13, 14. — Sower. Min. Conch, t. ccexxv.— In 



Carboniferous Limestone. 



21. T. lineata — Transvei'sely oval, gibbose; minutely striated longitudi- 

 nally, and transversely sulcated; sulci distant, Mart. Derb. xxxvi. f. 3. — Sower. 

 Min. Conch, t. ccexxxv. f. 1, 2 Carboniferous Limestone. 



22. T. imbricata. — Transversely oval, gibbose, imbricated, longitudinally 

 sulcated ; front slightly elevated ; sulci obsolete — Sower. Min. Conch, t. 

 ccccxxxv. f. 3, 4 — In Carboniferous Limestone. 



23. T. elongata. — Oval, convex, smooth ; margin even ; beak incurved. — 

 Sower. Min. Conch, t. ccccxxxiv. f. 1, 2. — In Chalk. 



24. T. sphceroida/is. — A depressed spheroid, with a slightly produced beak. 

 — Sower. Min. Conch, t. ccccxxxv. f. 3 Oolite. 



25. T. bullata — Orbicular, ventricose, with a produced and recurved beak ; 

 front indented ; depth greater than width. — Sower. Min. Conch, t. ccccxxxv. 

 f. A— Upper Oolite. 



26. T. emarginata.— Subrhomboidal ; the lesser valve nearly flat, the other 



