186 
CONOHIFERA. 
NaCQLA. 
Sub-rhoinboidal, two-thirds as long as wide, rounded, ven- 
tricose; anteriorly mucronated, and drawn out in the form of 
a flattened spine ; surface concentrically furrowed. 
A very minute species, found in the Great Oolite, And iff, 
Wiltshire. 
22 . Nucula angulata. —The Angled Nucula, pi. LXXVI. 
figs. 31, 32. 
N. angulata . Sowerby, V. p. 120 , pi. 4-70, fig. 5. 
Rhomboidal, its width about once and a-lmlf its length, front 
rounded : both sides equal, angular; their lines from the sides 
to the beaks almost straight; most convex near the beaks; 
surface with fine concentric furrows, rather inconspicuous to 
the naked eye. 
The Greensand, Blackdown. 
23. Nucula apiculata. —The Bee-like Nucula, pi. LXXVI. 
figs. 13, 14. 
N. apiculata. Sowerby, Geo. Tr. 2 d. Ser. p. 342, pi. 17, 
fig. 10 . 
Sub-orbicular, convex, anterior side rounded ; posterior side 
concave above, with the lower extremity much pointed ; sur¬ 
face smooth. 
The Greensand, Blacxdown. 
24. Nucula sub-compressa. —The Sub-compressed Nucula, 
pi. LXXVI. fig 90. 
N. undulata. Phillips, Geo. York, II. p. 210 , pi. 5, f. 16. 
Transversely ovate, compressed; both sides equally rounded ; 
beaks obtuse and approximating; surface with delicate, re¬ 
gular, concentric striae ; posterior sido with a depressed ridge. 
The Carboniferous Limestone, Holland. 
25. Nucula lineata. —The Lineated Nucula, pi. LXXVI. 
figs. 8 , 9, 10. 
N. lineata . Sowerby, Geo. Trans. 2 d Ser. IV. p. 342, pi. 
17, fig. 9. 
Elliptical; beaks nearly central, small, and hardly de¬ 
veloped ; anterior side rounded; posterior sido a little 
truncated, with a short point at its superior angle; surface 
transversely striated, which are straighter than the lines of 
growth, and consequently cross them twice. 
The Greensand, Blackdown. 
26. Nucula ckKnistri ata. —TheCrenistnated Nucula, pi. 
LXXVI. fig. 91. 
N. lineata. Phillips, Pal. Fos. p. 39, pi. 18, fig. 64. 
Deitoidal, or obliquely triangular; convex; sides nearly 
straight; surface smooth, with numerous close, transverse 
strim, every third or fourth being much more prominent than 
the others, and crenulatcd on their lower edge ; beaks obtuse, 
and approximating. 
A variety of this species lias the strias all even and plain. 
The Devonian Shales, in Limestone Nodules, Boggy Point, 
North Devonshire. 
27. Nucula sub-uecurva. —The Sub-recurved Nucula, pi. 
LXXVI. fig. 26. 
N. sub-recurva. Phillips, Geo. York, I. pi. 2 , fig. 11 . 
Transversely oblong-ovate; anterior side somewhat turned 
up, rather acute ; posterior side rounded ; beaks very obtuse ; 
surface smooth. 
The Specton Clay, Spccton, Yorkshire. 
28. Nucula axiniformis. —The Canopy-formed Nucula 
pi. LXXVI. fig. 34. 
N. axiniformis. Phillips, Geo. York, I. pi. 11, fig. 13. 
Transversely elongated; anterior sido terminating in an 
acute point, tho dorsal line being straight, and the basal 
line also nearly so; posterior side sub*acute, the superior 
line sloping downwards, and inclining suddenly from the 
centre; beaks obtuse; basal line gently curved; surface 
smooth. 
The Blue-Wick, Inferior Oolite, Yorkshire. 
29. Nucula rivirgata. —The Double-streaked Nucula, 
pi. LXXVI. fig. 44. 
N. bivirgata. Sowerby, Geo. Tr. 2d. Ser. IV. p. 335, pi. 
II, fig. 8. 
Obliquely sub-triangular, wider than long; very convex; 
back gently curved, ending in a sub-acute point; posterior 
side concave, with tho extremity pointed; base considerably 
arcuated, beaks obtuse, and approximating; surface with two 
sets of linear furrows, which converge towards tho posterior 
slope, where they meet at acute angles, directed towards the 
beak of each valve ; the junction producing a regular line, 
without forming a ridge; lunette broad; two transverse 
bands near tho base. 
The Gault, Folkstone. 
30. Nucula elliptica. —The Elliptical Nucula, pi. LXXVI. 
fig. 40. 
N. elliptica. Phillips, Geo. York, I. pi. 5, fig. 6. 
Elliptical; both extremities rounded ; anterior side short; 
beaks rather large, and turned anteriorly ; surface smooth. 
The Oxford Clay, Scarborough. 
31. Nucula piscm. —The Pea Nucula, pi. LXXVI. figs. 
46, 47. 
Sub-orbicular ; very convex; beaks obtuse, approximate ; 
both sides rounded, tho anterior one a little narrowed ; surface 
smooth. 
In the Coal Measures, near Newcastle-on-Tyne, bv 51 r 
Robertson. 
32. Nucula dubia. —The Dubious Nucula, pi. LXXVI. 
fig. 30. 
Nucula (?) Phillips, Geo. York, I. pi. 4, fig. 4. 
Transversely oblong-ovate; both extremities pointed; 
beaks very obtuse and nearly central; base gently rounded ; 
surface smooth. 
The Coralline Oolite, Malton. 
33. Nucula obtusa. —The Obtuse Nucula, pi. LXXT1. 
fig. 49. 
N. obtusa. Sowerby, Goo. Tr. 2d. Ser. IV. pi. 17, fig. 11. 
Transversely ovate, convex, and smooth ; lunette prominent, 
and elongated ; beaks rather obtuse. 
The Greensand, Blackdown. 
34. Nucula complanata. —The Flattened Nucula, pi. 
LXXVI. fig. 27. 
N. complanata. Phillips, Geo. York, I. pi. 12, fig. 8. 
Transversely elongated, anterior sido rounded ; posterior 
sido concave above, with a narrowed, sub-truncated, produced 
termination ; surface smooth. 
The Upper Lias Shale, Whitby. 
35. Nucula ovata. —The Ovate Nucula, pi. LXXVI. 
fig. 17. 
N. ovata. Phillips, Geo. York, I. pi. 2, fig. 10. 
Ovato; anterior side short and obliquely truncated; pos • 
