OSTREA. 
*Va Shell equivalve, hie thirty compreffed rays 
as with tranfverfe prickly f{cales; one ear very {mall. 
and 1 ; : 
of Eur pa varies very much in 
colour yao ple yellow to various fhades of orange and 
brown, with fometimes a few w fpets. The fhell is 
wrinkled plaits, and armed beneath with from five to feven 
ines. 
* Pusio. Shell equivalve, with about forty filiform rays, 
the furface often irregular or diftorted. faa is alae in 
Donovan’s Britifh Shells. It, is found in the European, 
Atlantic, and American feas. The fhell is ceil fall, 
and a little longer than it is broad ; etimes it is feen 
i 
* Og BSOLETA. 
Tnhabits 
ies eee Shell very {mooth ; ears ribbed. Inhabits An- 
glefea aad Falmouth, is more than half an inch long. 
reread Ears nearly or quite equal. Shell equivalve, 
m ten to fifteen {mooth flattifh rays; the infide 
with elevated double ftriz. It inhabits the European and 
fh ; 
shit, nis the upper ace. fore with brown ; 
margin nd 
a Oratue a Shell with about alaaiel rays, roundifh 
and rough, with decuffate ftriz ; valve a little 
more con There is a variety of this pec: 1t inhabits 
the Nowe feas of Europe ; and is two inches and a half 
long and broad. The fhell is gaping, generally variegated 
with {pots and other marks ; rays acute, fometimes rounded ; 
within ; 3 hei Py t 
i under 
the incifure. 
it is called frill or queen. 
Gripsa. Shell equivalve, Seta with twenty glabrous 
rays. It inhabits the American and Atlantic — h 
fhell is convex on each fide, ony with fom a few 
white fpots, and marked! hier fine crenate “Tongitudinal 
ftriz ; ioe te crenate ; ears n equal. 
Shell white ger ac colour = 3; the rays 
SuLcaTA 
sit one, thirty-two on the er valve, and twenty-five on 
the upper. It inhabits rie lores of Malabar ; is about one 
inch and a long, and fomething broa margin 
er; 
alve with an emarginate {pinous 
ne 
Shell thin, flattened, pellucid, with very 
fine tranfverfe wrinkles, and eleven rays. The fhell 1 
{potted with red, white, and black; rays waved; ears 
nearly equa 
Shell orbicular, with purple circles, and 
dred rays. Iti 
i he 
ale bloom or yel- 
lowith, and marked with tranfverfe femilunar bands ; upper 
valve more elegantly marked, with from fifty to one hundred 
rays, rough with acute imbricate f{cales; margin crenate ; 
ears with tran{verfe - uy = the large one emarginate 
and f{pinous: the fifhi 
RIRADIATA. 
Nor-vay. 
{pots, within reddifh ; upper valve with three rays; ovary 
of the fifth yellowi 
uci. Shell nearly ae ftriate, {potted, rough to- 
wards the margin. inha the North feas, on the 
e fhe I is rufous, with whitith or 
paler f{pots, within me and quite f{mooth, with pellucid 
oe ; a of the upper valve obfolete ; ovary of the fith 
re 
Shell nearly equivalve, ney i eae a 
It inhabits the North feas, on fuci 
eply groov a and seis a large un- 
upper valve dotted ; 
TIGERINA. 
with whitith = 
lower valve more de 
dulate ponaien: pale yellow fpots ; 
ovary of the fifth whit 
SEPTEMRADIaTA. Shel 
= with feven convex rays. 
feas. 
Arata. Shell nearly equivalve, within and without 
ved and red; one li art rough, the other glabrous. It 
® habits the North fea 
1 nearly equivalve, ftriate, pla- 
It inhabits the Noni 
ENATORIA. She i convex each fide, with oo 
rounded and tranfverfe wrinkled rays, the interftices wit 
longitudinal granulate ftriz. It inhabits the Indian ocean ; 
o inches nine lines long, and about as much broad; out- 
fide chefnut varied with violet and white ; infide violet, the 
circumference bordered with dull bay. 
Shell orange, with twenty-two rounded rays 
ries Er cai margin ; lower valve flatter. It inhabits India ; 
of the rays are {caly, and fome of the grooves have 
penn lines. 
Turcipa. Shell equally convex, both fides with Deen 
glabrous rays, the inter‘tices with tranfverfe crowded wr 
klee ; the margin with Sali teeth. It is found in the 
American and Indian 
ULPHUREA. Shell Aattened, Gea pellucid, ftriate, with 
numerous imbricate rays; the ma 
It inhabits the Red fea; is twoi 
orange hinge ae a femilunar 
d, or varied with ne and pa ale awny, Wh 
fanguineous border ; lower valve with equal nes thofe of 
the upper valve alternately lefs. 
Porpuyrea. Shell convex, purple, within white or red, 
with eh -five thick rounded {caly rays. s found in 
the Red fea; two inches three lines longs and as much 
broad ; fhell varied with a few white {po 
Virrea. Shell hyaline with an aes ae very flender 
rays, and concentric fcaly curves, It is found in the 
Nor th oe among fuci an zoophytes ; fize of a pea; thell 
{mooth, brittle, white, or varied with white and red; one 
ear emarginate and f{pinous. 
TRANQUEBARIA. 
reous fpots ; upper valve mo 
SauctaTa. Shell white, a arse {pots and numerous 
unequal rays; the margin crenate. Found in the Red 
Crenurata. Shell oblong, with undulate rays and 
frie, 
