148 
CONCHIFERA. 
Grypieea. 
undulations diverge from the central furrow; margins slightly 
foliatod. 
Great Oolite, Western Yorkshire. 
37. Ostrea indistincta. —The Indistinct Ostrea, pi. 
LVIII. fig. 8. 
Ostrea ? Geo. York, I. p. 109 and 180, pi. 5, fig. 12. 
Oblong, obliquely triangular, surface smooth. 
The Oxford Clay, Scarborough. 
38. Ostrea triangularis. —The Triangular Ostrea, pi. 
LXI.* figs. 9, 10. 
0. triangularis . Woodward, pi. YI. fig. G, 7. 
Triangular, oblong, oblique, with acute beaks ; surface rather 
smooth. 
In the Chalk, Norfolkshire. 
Genus XYIII.—GRYPILEA.— Lamarck. 
Shell free, inequivalve, upper valve small, flat, and acting 
apparently as a lid to the under one, which is large, concave, 
and arcuated, with an incurved prominent umbo; hinge des¬ 
titute of teeth, with a curved depressed area; provided in¬ 
teriorly with ono muscular impression in each valve. 
1. Grypieea incur v a. —The Incurved Gryphma, pi. LX. 
fig. 1. 
Gryphaa hicurva. Sowerby, II. p. 23, pi. 112, figs. 1, 2. 
Parkinson, p. III. 209, pi. 15, fig. 3. Goldfuss, pi. 84, fig. 1. 
Elongated ; larger valve greatly incurved, the point of the 
beak frequently concealed ; when visible, it is usually sharp, 
seldom exhibiting any impression; lesser valve a little ob¬ 
long, in the form of a lid, narrow towards the inner side, and 
gradually widening outwards, and externally concave ; surface 
considerably undulated concentrically; sometimes laminated; 
sides straight, gradually widening towards the rounded front. 
The Lias, of which it is a highly characteristic fossil, in 
England, Germany, and France. 
2. Grypiijea bullata.—T he Gem Gryphma, pi. LX. 
fig. 2. 
Gryphaa bullata . Sowerby, IY. p. 93, pi. 368. Phillips, 
Geo. York, I. p. 4, fig. 36. 
Transversely obovato, irregular, thin, smooth, and com¬ 
pressed ; upper valve considerably less than the other, which 
is undulated, concave, with concentric irregular lines of growth ; 
beaks very small, that of the lower valve much incurved ; lateral 
lobe small and obscure ; point of attachment very small. 
Kimmeridgo Clay, Bedford and Norfolk, the Middle 
Oolite, Wiltshire and Yorkshire. 
3. Grypllea Macullochii. —Maculloch’s Gryphma, pi. 
LX. fig. 19. 
Gryphma Macullochii . Sowerby, YI. p. 89, pi. 547. 
Goldfuss, pi. 64, fig. 4. 
Longitudinal, obovato, gibbose, and oblique; beaks much 
produced and incurved ; base rather angular; posterior lobe 
more or less distinct; surface strong, with curved lines of 
growth. 
This fossil is intermediate between G. incurva and G. dila~ 
tata, , but is much shorter than the latter and greatly thicker. 
Lias, at Pabba and Scalpa, Hebrides, and Robin IIood’6 
Bay. 
4. Grypilea Columba.—T he Pigeon Gryphma, pi. LXI. 
fig. 15. 
G. Columba . Sowerby, IY. p. 113, pi. 383, figs. 1 and 2. 
Exogyra Columba. Goldfuss, pi. 86, fig. 9. 
Ovato ; rounded; beak nearly central, much attenuated ; 
incurved obliquely; posteriorly expanded ; surface smooth ; 
upper valve slightly striated near the hinge, and more or 
less quadrangular; largely undulated; its posterior margin 
thick and flattened; opposite valve obtusoly carinated. 
Greensand, Lyme and Devonshire. 
5. Gryph/Ea depressa.—T he Depressed Gryphma, pi. 
LXI. figs. 19. 
G. depressa. Phillips, I. p. 134, pi. 14, fig. 7. 
Ovate, oblique ; beaks obtuse, turned to ono side ; margins 
and surface smooth, with distinct lines of growth ; flat valve 
nearly plain. 
Lias, Bilsdale, Yorkshire. 
6. Grypieka dilatata.*—T he Extended Gryphma, pi. 
LXI, fig. 1, 6, 7. 
G. dilatata. Sowerby, II. p. 113, pi. 149, figs. 1, 2, variety 
Phillips, I. p. 112. pi. 6, fig. 1. 
Orbicular, obscurely lobed, upper valve compressed, quite 
flat, with an obtuse umbo; under valve hemispherical, with 
its umbo rather large and incurved, remote from that of the 
other valve. 
The variety, fig. I. has a distinct lobe, and longitudinal furrow on the 
narrow side of the deeper valve. 
Portland Sand, Langcomb, Oxon; Kimmerldge Clay, Bed¬ 
ford ; Ivelloways Rock; Scarborough and Ilackness, and the 
inferior Oolite, near Cheltenham. 
7. GrypHjEA gigantea.—T he Gigantic Gryphma, pi. 
LXI. fig. 5. 
Gryphaa gigantea. Sowerby, IY. p. 127, pi. 391. Gold¬ 
fuss, pi. 85, fig 5. 
Nearly orbicular; upper valve thin and concave; lower 
valve convex, with a small, sharp, incurved umbo; hinge 
small ; surface rather smooth, with imbricated laminm, which 
in the lessor valve are hut slightly developed, even, and situate 
at regular intervals ; anterior lobo separated by a small sinus 
in the edge of the laminm ; depth about a fifth of its length. 
It is probable that G . bullata and dilatata are only varieties of this 
species. 
Great Oolite, White Nab; Inferior Oolite, Ilminster and 
Lias, Prees. 
8. Grypieea globosa— 1 The Globular Gryphma, pi. LXI. 
fig. 2. 
G. globosa. Sowerby, IY. p. 127, pi. 392. Ostrea fassicu- 
laris , Brongniart, Env. de Paris, pi. 3, fig. 5. 
Obliquely subglobosc, thin and smooth ; beak much trun¬ 
cated ; upper valve concave; hinge-line straight ; anterior 
lobo very conspicuous; a small additional muscular impres¬ 
sion situate near the hinge. 
Upper Chalk, Gravesend and Sussex ; and the Red Chalk 
Hunstanton. 
9. Gryphaa nana—T he Dwarf Gryphma, pi. LXI. figs. 
3j 4. 
G. nana. Sowerby, IV. p. 114, pi. 383, fig. 3. 
Oblong-ovate, inflated ; surfaco rugged ; umbo pointed, 
obliquely incurved; upper valve acute and thick; variable in 
