Terebratula. 
MOLLUSCA. 
135 
Upper Greensand, Chute Farm; Gault, Cackerton and Hunt- 
stanton; Lower Greensand, Parham and Sandgate. 
42. Terebratuua sph^roidalis _The Spaeroidal Tere¬ 
bratula, pi. LV.* fig. 36, 37. 
T. sphceroidalis. Sowerby, V. p. 49, pi. 435, fig. 3. 
Nearly sphaeroidal, very slightly compressed; beak produced, 
and incurved ; edges of valves even ; surface smooth. 
Inferior Oolite, Dundry, Somersetshire. 
43. Terebratula subrotunda. —The Subrotund Tere¬ 
bratula, pi. LV.* fig. 40, 41. 
T. subrotunda. Sowerby, I. p. 45, pi. 15, fig. 1, 2. 
Nearly circular,compressed; both valves regularly and equally 
convex; beak short, very slightly curved, and angular on each 
side; surface smooth. 
In some specimens the larger valve is a little deeper than the other. 
Upper and Lower Chalk, Norfolk, Lewis, and Hamsey. 
44. Terebratula obovata. —The Obovate Terebratula, 
pi. LV. fig. 43. 
T. obovata. Sowerby, I. p. 228, pi. 101, fig. 5. 
Obovate; sides slightly rounded; subdepressed; margin rather 
flat; base nearly parallel, bounded by two nearly obsolete plaits; 
beak rather produced. 
Lias, Chatley, Somersetshire. 
45. Terebratula proava. —The Great-Grandfather Te¬ 
rebratula, pi. LV.* fig. 52. 
T. proava. Phillips, II. p. 223, pi. 12, fig. 37. 
Oblong; larger valve with the beak considerably produced; 
having a square mesial fold; valves with numerous, rather ob¬ 
tuse, and large radiating ribs. 
Carboniferous Limestone, Bolland, Yorkshire. 
46. Terebratula bidentata —The Two-toothed Tere¬ 
bratula, pi. LVI. fig. 31, 32. 
T. bidentata. Sowerby, Sil. Syst. p. 625, pi. 12, fig. 13 a. 
Dalman, 1. c. p. 142, pi. 6, fig. 5. Hist. Act. Holm. 1826, pi. 
7, fig. 5. 
Triangular, smooth, depressed; strongly and acutely plaited, 
about eight of which in the front are raised. Length three 
lines ; width three lines and a half. 
Wenlock Limestone, Dudley and Abberley. 
47. Terebratula cuneata —The Wedge-shaped Tere¬ 
bratula, pi. LV.* fig. 1, 2. 
T. cuneata. Sowerby, Sil. Syst. p. 625, pi. 12, fig. 13. Dal- 
main, Act. Holm. pi. 6, fig. 3. Hist. Pet. Suec. p. 81, pi. 23, 
fig. 5. 
Triangular, its length exceeding its width; beak of the larger 
valve straight, and produced ; surface with from ten to twelve 
plaits, of which a few in the front are elevated. Length half 
an inch ; depth of each valve two lines. 
Wenlock Limestone, Wenlock; Dudley, Lincoln Hill, and 
Abberley. 
48. Terebratula bifera —The Double Terebratula, pi. 
LVI. fig. 76, 77. 
T. bifera. Phillips, Pal. Fos. p. 84, pi. 34, fig. 154. 
Tetrahedral, with four of the angles rounded, two of the 
sides almost straight, the other two concave; beak acute; upper 
valve trilobate, the middle one longest, and elevated towards 
the base; surface with numerous, fine, radiating striae, which 
are bifurcate, at unequal distances from the beaks, particularly 
towards the margins, where they are from 50 to 60 in number. 
Devonian Shales, Hope, near Torquay. 
49. Terebratula deflexa.—T he Bending Terebratula, 
pi. LV* fig. 81, 82. 
T. dejtexa. Sowerby, Sil. Syst. p. 625, pi. 12, fig. 14. 
Transversely obovate, gibbose; lower valve with a sinus; 
beaks small, and adpressed; with about twenty-four sharp plaits, 
of which the four or five central ones in front are turned down¬ 
wards. Length nearly five lines; width six lines; depth four 
lines and a half. 
A peculiarity in this species ie the sinus being in the larger valve. 
Wenlock Limestone, Wenlock Edge. 
50. Terebratula Gallina. —The Fowl Terebratula, pi. 
LVI. fig. 78, 79. 
T. Gallina. Brongniart, Env. de Paris, pi. 9? fig. 2. Wood¬ 
ward, Geo. Nor. p. 49, pi. 6, fig. 12. 
Transversely obovate; moderately convex; lower valve with a 
wide, central furrow; beak rather acute, and small; both valves 
with wide, pretty large, numerous, longitudinal, divergent ribs. 
Under-Chalk formation, Harford Bridge, Norfolk. 
51. Terebratula Wilsoni. — Wilson’s Terebratula, pi. 
LV* fig. 90, 91. 
T. Wilsoni. Sowerby, II. p. 38, pi. 118, fig. 3. Ib. Sil. Syst. 
p. 615, pi. 6, fig. 7 a. T. lacunosa , Wahl. Dalman, 1. c. cil. p. 
139, ph 6, fig. 1. Hisingcr, Pet. Suec. p. 80, pi. 23, fig. 3. 
Circular, plaited; valves compressed near the beaks; base 
cylindrical, the seven central plaits elevated, margin acutely 
dentated, and with nine or ten plaits on each side; front sinus 
deep. 
This species is highly characteristic of the central Ludlow 
Rock, Aymestry Limestone, Salop; Radnor, Hereford; Aymes- 
try, and Eastnor Park. 
52. Terebratula Unguis —The Cloven Terebratula, 
pi. LVI. fig. 36. 
T. Unguis. Sowerby, Sil. Syst. p. 640, pi. 21, fig. 13. 
Orbicular, much inflated; beak incurved; with about twelve 
large, sharp plaits. Length 5i lines ; width 5 lines. 
Caradoc Sandstone, Horderley and Welshpool. 
53. Terebratula pusilla. — The Slender Terebratula, 
pi. LVI. fig. 18. 
T. pusilla. Sowerby, Sil. Syst. p. 641, pi. 21, fig. 18. 
Almost globose, with about fourteen sharp plaits, four of them 
elevated on the base. Diameter nearly four lines. 
Lower Silurian Rocks, Cefn, Rhyddan, Llandovery. 
54. Terebratula tripartita. —The Three-parted Tere¬ 
bratula, pi. LVI. fig. 29* 
T. tripartita. Sowerby, Sil. Syst. p. 641, pi. 21, fig. 15. 
Transversely oval, convex; with from fifteen to twenty rough 
plates, frequently furcated; centre much elevated, so as to divide 
the surface into three nearly equal parts. Length half an inch; 
width one inch and two lines. 
Caradoc Sandstone, Goleugocd, Llandovery. 
55. Terebratula decemplicata _The Ten-plaited Te¬ 
rebratula, pi. LV.* fig. 88. 
T. decemplicata. Sowerby, Sil. Syst. p. 641, pi. 21, fig. 17. 
Almost globular; beaks small, rather acute; with ten angular 
plaits, two of them much elevated on the base. Length four 
lines; width four lines and a half. 
Caradoc Sandstone, Eastnor Park; Ankerdine Hill; May 
Hill; Prescoed Common, Usk. 
