Tebebkatula. MOLLUSCA. ACEPHALA. 371 
convex ; front defined by two angles, or emarginate ; edge becoming blunt 
by age. — Sower. Min. Conch, t. ccccxxxv. f 5 — Upper Oolite. 
27* T. globata Subglobose ; front elevated with two obtuse folds, and 
slightly produced ; surface often minutely punctated — Sower. Min. Conch, 
t. ccccxxxvi. fi 1 — Upper Oolite. 
2d. T. joprwa/is.— Ovate, convex, with two elevated sinuses at the front, 
which is depressed between them ; beak incurved — Sower. Min. Conch, t. 
ccccxxxvi. f. 2, 3. — Under Oolite. 
29. T. maxillata. — Subquadrangular, convex ; two acute rising sinuses in 
the front, and one obtuse sinus on each side ; three conspicuous furrows in 
the upper, and two in the lower valve ; front rounded — Sower. Min. Conch, 
t. ccccxxxvi. f, 4t.— Upper Oolite. 
30. T. Sella — Subquadrangular, convex ; front considerably elevated, nar- 
row, emarginated when old ; sides depressed, slightly rounded. — Sower. Min. 
Conch, t. ccccxxxvii. f. 1. — Upper Oolite. 
31. T. ohtusa — Suborbicular, rather depressed ; front broad, elevated ; 
edge obtuse. — Sower. Min. Conch, t. ccccxxxvii, f. 4.o— From Cambridge. 
32. T. ohesa — Ovate, gibbOse, front elevated considerably, with a slight 
broad sinus in the middle ; beaked valve regularly convex to the edge ; beak 
incurved, short.— Min. Conch, t. ccccxxxviii. f. 1. — In Chalk. 
33. T. hucculenta. — Father square, with rounded sides, convex ; front pro- 
duced, truncated, very slightly elevated ; beak short — Sowen Min. Conch, 
t. ccccxxxviii. f. 2. — In Green Sand. 
34. T. Suborbicular, with a produced incurved beak ; valves 
equally convex ; front slightly indented ; beak obtusely keel-shaped, with a 
Carina on each side — Sovjer. Min. Conch, t. ccccxlv. f. 1. — In Oolite. 
35. T. indentata. — Elliptical, smooth, more or less gibbose ; valves equally 
convex; front deeply notched; beak small, much incurved.— Min. 
Conch, t. ccccxlv. f. 2. — In Limestone at Banbury. 
36. T. Sacculus.~-OhoY 2 ite^ gibbose, with a longitudinal groove along the 
larger valve ; the smaller valve slightly grooved ; front emarginate.— Anomia 
Isevis, Ure's Futh. 313. t. xvi. f. 9. — A sacculus, Martin’s Derb. t. xlvi. f. 1, 2. 
—Ter. Sacc. Sower. Min. Conch, t. ccccxlvi. f. 1. — In Carboniferous Limestone. 
37 . T. hastata. — Elliptical, subrhomboidal, rather depressed ; front trun- 
cated and indented ; edges sharp.— iS'ozcer. Min. Conch, t. ccccxlvi. f. 2, 3. — 
Greywacke Limestone, Cork. 
38. T. comw^a.— Short, convex, with blunt edges, four-lobed ; the two 
middle lobes produced ; the others very short. — Smwr. Min. Conch, ccccxlvi. 
f. 4.— In Oolite. 
39. T. ambigua. — Subpentangular, gibbose, perforated valve with a broad 
mesial groove, with a mesial ridge, having a shallow central furrow enlarging 
at the margin. — Spirifer ambiguus, Sower. Min. Conch, t. 376 — Carboniferous 
J.imestone. 
** Margin of the valves dovetailed. 
40. T. lateralis.— OvoX, broader than long, gibbous ; middle of the front 
much elevated, with three deep but short plaits ; sides with two plaits each, 
much below the middle.— Min. Conch, t. Ixxxiii. f 1.— In Carbonife~ 
rous Limestone. 
41. T. crMw^na— Deltoid, gibbous, plaited; middle of the front elevated, 
A a 
