48 TESTACEOUS MOLLUSCA. 
anterior side the longer attenuated and slightly truncated: ventral 
edge slightly incurved. 3.— Rochelle in rocks.! = Shiaeea ls bovba 
MUG < 
PANDORA. 
Shell regular, inequivalve, inequilateral, and transversely oblong ; 
upper valve flattened, and the under one convex ; hinge nith 
two oblong diverging cardinal teeth, in the upper valve, and the 
other valve with two oblong grooves ; ligament internal. 
P. Ostusa.* Lam. 2.—Sow. Sp. Con. f. 1, 2, 3.—Del. t. 4. 
Jf. 8.—Tevtiina Pinna. Pennant. t. 67. f. 3.—Soxien. P. 
Mont. t.15.f.3.—W. t. 3.f. 35. Ovate, posterior side very short, 
obtuse and obliquely rounded ventrally, slightly angular dorsally : 
narrower than the anterior which is much lengthened and 
dilated: posterior dorsal edge nearly straight and angulated at the 
end, dorsal edge of the flat valve over-lapping the concave one. 
y+ qh. — England. 
P. Rosrrata.* Lam. 1.—Sow. G.—Sow. Sp. Con. f, 7, 8, 
9.—Teiuina Inequivatvis. Lin. 1118.—D. p. 86.—Don. t. 
41.f. 1.—Turt. Biv. t. 3. f. 11. to 14.—H. t. 250. f. 1.— Ch. ff. 

! It is scarcely possible from the imperfect description, to decide 
whether this shell is the Anatina Truncata of Turton, or a Sphenia. 
I give the characteristics of the former from Turton. 
A. Truneata.* Turt. Biv. p. 46. t. 4. f. 6. Convex, wedge- 
shaped, slightly angular and truncated anteriorly, abruptly truncated 
posteriorly, rough, transversely striated; ventral edge nearly 
straight : teeth projecting a little inwards but running obliquely.— 
England. 
Mr. Reeve in his systematic Conchology, has placed as ap- 
proximating to this genus, 
MYOCHAMA. Stutchbury. 
Inequivalve, adhering ; the attached valve with two unequal diverging 
marginal teeth, separated at the umbo by a triangular pit, m which 
one end of a testaceous appendage is inserted and connected by a 
horny cartilage ; the free valve with two unequal small diverging 
teeth close under the umbo, in which is inserted the other end of 
the testaceous appendage. Umbo of the free valve curved inwards, 
that of the fixed valve outwards. Muscular impressions two, nearly 
orbicular, distant, lateral ; palleal scar with a short broad sinus. 
Ligament thin, external. 
M. Anomoiprs. Stutch. Z. J. 5. sup. t. 42. f. 1, to 4.— 
Reeve. t. 39. Rose coloured, thin, with prominent radiating dichoto- 
mous ribs. Free valve extremely convex, the umbo projecting beyond 
the apex of the other ; epidermis thin and transparent. 5°>..43. 
