150 
CONCHIFERA. 
Plicatula. 
canaliculated appendage; and with its umbo curved towards 
the wing ; beak of the opposite valve rather short. 
The Upper Greensand, Western Lines, Isle of Wight, and 
the Greensand, Blackdown and Lyme Regis. 
24. Gkypha2a mima.—T he Mimic Gryphma. 
Gryphcea mima. Phillips, Geo. York, I. pL 4, fig. 6. 
The Coralline Oolite, Mai ton, and Calcareous Grit. 
25. Guypiiasa suilla. The Swine Gryphsoa, pi. LXI.* 
fig. 14. 
G. suilla. Goldfuss, p. 30, pi. 85, fig. 4. 
Sub-orbicular, with concentric striated laminae; the su¬ 
perior valve plain ; the inferior one with a short blunt oblique 
beak ; the lateral edges of the lips turned much inwards. 
The Lias, near Cheltenham. 
26. Gryphjea virgula. —The Fallen Gryphma, pi. 
LXVI.** figs. 25, 26. 
Exogyra virgula. Sowerby, Geo. Tr. 2d Ser. IV. pi. 23, 
fig. 10. Goldfuss, pi. 86, fig. 3. 
Greatly elongated and arcuated ; one valve convex, with 
elevated lines, the other flat. 
The Kimmeridge Clay, Aylesbury, Buckinghamshire. 
27. GRYPDiEA inhjERENS. —The Inherent Gryphsea. 
G. inhwrens. Phillips, Geo. York, I. p. 163. 
The Coral Rag and Calcareous Grit, Mai ton, &c. 
28. Grypu/Ea cymbium. —The Boat Grypluea, pi. LXI.* 
figs. 22, 23. 
G. cymbium. Goldfuss, p. 29, pi. 85, fig. 1. 
Oblong-ovate; the superior valve concave, concentrically 
striated ; the lower valve boat-shaped, and concentrically 
lineated and striated ; beak acuto and turned to one side; 
length 5 \ inches; breadth 3^. 
Inferior Oolite, Cotswold Hills. 
29 . Gryphasa decussata.— The Decussated Gryphrca, 
pi. LXI.* figs. 15, 16. 
G. decussata. Goldfuss, II. p. 35, pi. 86, fig. 11. 
The lower valve oblong-oval, convex, with the apex later¬ 
ally attached ; surface with decussated waved striae. 
The Chalk, Northfleet. 
30. GuYrUjEA aquila. The Eagle-beaked Grypluea, pi. 
LXI* figs. 17, 18, 19. 
G. aquila. Goldfuss, pi. 87, fig. 3. 
Obliquely sub-triangular, larger valve deep, with an undu¬ 
lated ridge, emanating from the beak and ending on the base, 
from whence the side is abruptly flattened, and wrinkled ob¬ 
liquely, with an undulating margin; from the ridge to the 
posterior side the valve gradually slopes, and its surface is 
transversely waved and wrinkled longitudinally towards the 
base; beak large, and much turned to one 6idc; upper 
valve fiat, with an obtuse beak; smooth and uneven in the 
centre, and the other portion with many concentric broad 
striae. 
This is a largo species, measuring 4^ inches in length and 
3^ in breadth. 
The Lower Chalk, Sussex. 
Family II.—PECTINIDES. 
Ligament placed interiorly, or partly so ; shell in general 
irregular, compact, and not foliaceous. 
Genus XIX.—PLICATULA.— Lamarck. 
Shell irregular, inequivalve, and destitute of ears, attenu¬ 
ated at the base, rounded and plaited at the upper margin; 
umbones unequal and entire ; bingo with two strong, gene¬ 
rally perpendicularly grooved teeth in each valve, with 
their points recurved, and a central cavity or pit for the 
reception of the ligament, which is internal; under valve 
generally more convex than the upper one; muscular im¬ 
pressions strong, orbicular, and situate near the centre of 
tho valves. 
1. Plicatula spinosa. —Tho Spinous Plicatula, pi. 
LXII. figs. 1, 2. 
P. spinosa. Sowerby, III. p. 79, pi. 245. Phillips, I. p. 
134, pi. 14, fig. 15. Goldfuss, pi. 107, fig. 1. 
Obliquely-ovate, compressed, with an angle at the beaks; 
deeper valve, with radiating undulations, and numerous sharp 
spines; opposite valve externally concave, and destitute of 
undulations, but with irregular sharp hollow spines, which are 
frequently hooked ; margins entire. 
Lias, Lyme Regis, and Yale of Gloucestershire, Yorkshire, 
and Hebrides. 
2. Plicatula pectinoides.— The Pectinated Plicatula, 
pi. LXII. 3, 4. 
P. pectinoides. Sowerby, Y. p. 5, pi. 409, fig. 1. P. ra- 
diata. Goldfuss, pi. 107, fig. 7 (?) 
Oblong-ovate, curved and depressed ; beaks curved and 
projecting ; surface with numerous longitudinal, divergent 
ridges, surmounted by many depressed irregular spines; free 
valve externally concave. When old this shell is frequently 
sub-globose. 
Chalk Marl, Cambridge, Dover, &c.; Lower Greensand, 
Court-at-Street, and Broughton. 
3. Plicatula inflata. —The Inflated Plicatula, pi. LXII. 
fig. 5. 
P. inflata. Sowerby, V. p. 6, pi. 409, fig. 2. P. spinosa. 
Man tell, Goo. Suss.pl. 26, figs. 16,17. Goldfuss, pi. 107, fig. 6. 
Sub-orbicular, gibbose; both valves convex; beaks nearly 
central, and rather obtuse; surface rather smooth, and pro¬ 
vided with a fow longitudinal ridges, mostly emanating from 
the disc, and terminating on the base, each furnished with a 
few depressed spines. 
Chalk Marl, Cambridge and Sussex; Upper Greensand, 
Petersfield and Islo of Wight. 
Genus XX.— PLAGIOSTOMA.— Lluyd. 
Shell inequilateral, sub-equivalve, oblique, and provided 
with small oars, mostly higher than long; generally covered 
with grooves or stria? diverging from tho umbones, and pass¬ 
ing to tho basal margin; hinge-line transverse, straight, 
oblique, and destitute of teeth ; umbones remote; depression 
for tho ligament either straight or slightly angular. 
L Plagiostoma giganteum. —Tho Gigantic Plagiostoma, 
pi. LXVI. fig. 10. . 
P. gigantea. Sowerby, I. p. 176, pi. 77. Goldfuss, pi. 
101, fig. 1. 
Obliquely-oblong, sub-compressed, and deltoidal, with the 
posterior side rounded into the front; umbones, nearly 
