NucrLA. 



CONCHIFERA. 



18/ 



terior side elongated and rounded ; beaks very obtuse ; surface 

 smooth. 



The Sjiecton Clay, Speeton, Yorkshire. 



3(5. NucuLA ACCiPiENs. — Tiio Admitted Nucula, pi. LXXVI. 

 figs. .50, JT- 



X. acci/nms. Sowerby, Geo. Tran. 2d. Ser. V. pi. 39, f. 4. 

 Transversely elongated ; oblong-oval ; much compressed ; an- 

 terior side rounded ; posterior side truncated ; beaks nearly 

 central ; surface with fine, regular, concentric stria\ 



The Coal Measures, Coalbrook Dale, Stafl'onlshire. 



37. Nucula acuta. — The Acute Nucula, pi. LXXVI. fig. 

 58. 



X. acuta. Sowerby, Geo. Trans. 2d. Ser. V. p. 639, fig. 5. 



Transversely oblong, convex ; anterior side rounded ; pos- 

 terior side acuminated, and terminating in a sharp point ; 

 beaks rather acute, and sub-central ; surface with fine con- 

 centric stria;. 



The Coal ^Measures, Coalbrook Dale. 



38. Nucula ^equalis. — The Equal Nucula, pi. LXXVI. 

 fig. 59. 



X. (vqualis. Sowerby, Geo. Tr. 2d Ser. V. pi. 39, fig. 3. 



Transversely sub-ovate ; convex ; anterior side short, round- 

 ed ; posterior side separated by a ridge and truncated ; beaks 

 situate nearest the anterior side ; surface witli numerous fine 

 concentric ridges. 



The Coal Measures, Coalbrook Dale, Staffordshire. 



39. Nucula attenuata. — The Attenuated Nucula, pi. 

 LXXVI. fig. 70. 



X. atteiiuata. Fleming, Brit. An. p. 403. Ure, Hist. 

 Rutherglen, &c. pi. 15, fig. 5. 



Transversely elongated, greatly arcuated, ventricose ; an- 

 terior side short, obliquely truncated ; posterior side much 

 elongated and attenuated, terminating in a blunted point ; 

 hinge area wide and very concave ; beaks much produced, a 

 little incurved ; surface with fine, delicate, transverse strisB ; 

 base much arcuated. 



Coal Shale, Renfrewshire. 



40. Nucula brevirostba. — The Short-beaked Nucula, 

 pi. LXXVI. fig. 74. 



X. hretirostra. Phillips, Geo. York, II. p. 210, pi. 5, 

 fig. \\a. 



Ovate, anterior side short and attenuated ; posterior side 

 large and rounded ; beaks short ; surface with fine concentric 

 striiu ; back and base equally curved. 



The Carboniferous Limestone, Ilarelaw, Northumberland. 



+ 1. Nucula longirostra. — The Long-billed Nucula, pi. 

 LXXVI. figs. 68, 69. 



N. clatiformu. Phillips, Geo. York, II. p. 210, pi. 5, 

 fiir. \1a. 



Claviforni, nmch elongated, transversely convex ; anterior 

 side roiiudod ; posterior side lengthened, and rapidly attenu- 

 ated, with the termination acute ; beaks short, a little incurv- 

 ed ; bas<il line ascending abruptly from the point opposite 

 the beaks. 



The Carboniferous Limestone, Harolaw and Otterburn, 

 Northumberland. 



42. Nucula gibbosa. — The Tumid Nucula, pi. LXXVI. 

 fig. 79. 



N.gihhosa. Fleming, Brit. An. p. 403. Ure, Kutherglen. 



p. 310, pi. 15, fig. 0. Phillips, Geo. Y'ork, II. p. 210, pi. 5, 

 fig. 15. 



Transversely ovate, ventricose ; anterior side short ; poste- 

 rior longer and rounded ; beaks obtuse and incurved ; surface 

 with shallow remote lines of growth. 



The Coal Shale, Renfrewshire. 



43. Nucula luciniformis. — The Lucina-formed Nucula, 

 pi. LXXVI. figs. 80, 81. 



X. luciniformis. Phillips, Geo. Y'ork, II. p. 210, pi. 5, 

 fig. 11. 



Obliquely ovate ; inflated ; smooth ; anterior side rounded ; 

 posterior side obliquely truncated, with some narrow striae ; 

 base considerably arcuated. 



The Carbouiferous Limestone, Bolland. 



44. Nucula cuneata. — The Wedge-shaped Nucula, pi. 

 LXXVI. fig. 72. 



X. cuneata. Phillips, Geo. Y^ork, II. p. 210, pi. 5, fig. 14. 



Transversely elongated ; wedge-shaped ; beaks obtuse, situ- 

 ate near the anterior end ; hinge-line straight, and extending 

 nearly the whole breadth of the shell ; anterior end narrow, 

 and increasing in breadth towards the other extremity, which 

 is rounded ; surface with a few remote, radiating strise, and 

 concentric lines of growth. 



The Carboniferous Limestone, Bolland. 



45. Nucula Bowerbankii. — Bowerbank's Nucula, pi. 

 LXXVI. figs. 82, 83. 



X. Boicerhankii. Sowerby, Geo. Tr. 2d Ser. V. p. 136, pi. 

 8, fig. 11. 



Sub-elliptical, convex ; anterior side obliquely truncated, 

 with a nearly flat, pointed lunette, occupying the whole side ; 

 posterior side rounded ; external surface smooth, striated in- 

 ternally; edge toothed; impressions of the obductor muscles 

 shallow. 



The London Clay, Hampstead Heath. 



46. Nucula Wetherellii. — Wetherell's Nucula, pi. 

 LXXVI. figs. 76, 77. 



X. Wetherelln. Sowerby, Geo. Tr. 2d Ser. V. p. 136, pi. 

 8, fig. 12. 



Nearly orbicular; gibbose ; smooth; both sides slightly 

 pointed ; beaks small, nearly central ; hinge-line triangular ; 

 margin crenulated. 



The Loudon Clay, Hampstead Heath. 



47. Nucula compressa. — The Compressed Nucula, pi. 

 LXXVI. figs. 63, 64. 



X. compressa. Sowerby, Geo. Tr. 2(1 Ser. V. p. 136, pi. 8, 

 fig. 14. 



Sub-ovate, smooth ; compressed ; anterior side rather short, 

 contracted, and a little pointed ; posterior side large and 

 rounded ; base arcuated ; destitute of a lunette. 



The London Clay, Hampstead Heath. 



48. Nucula striata. — The Striated Nucula, pi. LXXVI. 

 figs. 60, 01. 



X. striata. Variety, Sowerby, Geo. Tr. 2d Ser. V. p. 136, 

 pi. 8, fig. 13. 



Transversely elliptical ; anterior side rather short, and a 

 little pointed ; posterior si<le rounded, acute above ; hinge-line 

 straight; external surface with very fine concentric striw. 



The London Clay, Hampstead Heath. 



49. Nucula .vuda. — The Bare Nucula. p!. LXXVI. f. 75. 



