372 MOLLUSCA. ACEPHALA. Terebratula. 



with three long plaits ; sides with four or more plaits below the middle ; 

 beak prominent — Anomia striata, Ure, Ruth. 313. t. xiv. f. C. — Ammonites 

 crumena, Mart. Derb. t. xxxvi. f. 4 — Ter. erum. Soiver. Min. Conch, t. 

 lxxxiii. f. 2, 3. — Carboniferous Limestone. 



42. T. tetraedra — Obtusely deltoid, gibbous, plaited ; front elevated in the 

 middle, with four or five sharp plaits ; four or more sharp plaits on each side ; 

 beak rather incurved — Sower. Min. Conch, t. lxxxiii. f. 4. — In Oolite. 



43. T. media. — Very obtusely deltoid ; gibbous, plaited ; front rounded, 

 with a rising in the middle, composed of six sharp plaits approaching those 

 in the middle ; beak a little incurved. — Sower. Min. Conch, t. lxxxiii. f. 5. — 

 In Oolite. 



44. T. concinna — Nearly globose ; acutely plaited ; middle elevated by 



seven plaits ; twelve or more plaits on each side ; beak projecting Sower. 



Min. Conch, t. lxxxiii. f. 6 In Oolite. 



45. T. obsoleta — Nearly round, gibbous, plaited ; middle of the front a lit- 

 tle elevated by seven plaits ; sides having from seven to eleven plaits ; beak 

 projecting — Sower. Min. Conch, t. lxxxiii. f. 7. In Oolite. 



AG. T. plicatilis. Gibbose, transversely obovate, finely and obtusely plait- 

 ed ; middle elevated by twelve plaits ; fifteen or more plaits on each side ; 

 beak slightly projecting. Soiver. Min. Conch, t. cxviii. f. 1. In Chalk. 



47- T. ocloplicata. Gibbose, transversely obovate, obtusety plaited ; middle 

 elevated by eight plaits; twelve or fourteen plaits on each side; beak pro- 

 jecting. Sower. Min. Conch, cxviii. f. 2. In Chalk. 



48. T. Wilsoni. — Circular, plaited ; front cylindrical, margin acutely den- 

 tated, elevated in the middle with seven plates, nine or ten plates on each 

 side ; valves compressed towards the beaks. — Sower. Min. Conch, t. cxviii, 

 f. 3— In Carboniferous Limestone at Mordiford, E.S.E. of Hereford. 



49. T. pectita. — Orbicular, gibbose, plicato-striated, with a flattish space 

 extending from the front to the beaks ; beak of the lower valve prominent, 



slightly incurved, back of the upper valve straight, with an incurved beak 



Sower. Min. Conch, t. exxxviii. f. 1.— In Green Sand. 



50. T. Lyra. — Oblong, convex, with diverging furcated plaits ; beak of the 

 lower valve greatly elongated, with two longitudinal septa, that of the up- 

 per valve short, incurved — Sower. Min. Conch, t. exxxviii. f. 2 In Green 



Sand. 



51. T. acuta — Ovato-triangular, slightly transverse; middle elevated by 

 one large acute angular plait; sides with one large and several small, plaits 

 each — Sower. Min. Conch, t. cxl. f. 1, 2 Inferior Oolite. 



52. T. Mantice. — Depressed, subtrigonous ; with 10 angular plaits, half of 

 them on one side elevated; upper valve convex — Sower. Min. Conch, 

 t. eclxvii. f. 1. — Carboniferous Limestone, Ireland. 



53. T. obliqua — Depressed, transversely obovate, with 15 angular plaits, 

 the 5 central ones obliquely elevated from one side ; beak prominent — Sower. 

 Min. Conch, t. eclxxvii. £ 2 In Chalk. 



54. T. inconstans — Globose, with about 26 angular plaits, half of them, on 



one side, elevated ; beak incurved.— Soiver. Min. Conch, t. eclxxvii. f. 3, 4 



Middle Oolite. 



55. T. dimidiata — Transversely obovate, subdepressed, with a projecting 

 beak, plaited ; upper valve convex; plaits about 30, half of which, on one 

 side, are elevated — Sower. Min. Conch, t. eclxxvii. f. 5.— In Green Sand. 



