OSTREA. 
133 
the sixteen middle ones placed in fours ; that is, there are 
four of these quadruple series between the grooves corre¬ 
sponding with the rays on the outside, the two middle sets 
of which are near together, the others being remote, the 
colorpaler than the outside except near the hinge : length 
three quarters of an inch ; breadth rather less. 
Coast of Dunbar: very rare. 
i 11. Ostrea obsoleta. Obsolete Scallop. 
Pennant , pi. 64. f. 3— Donovan, pi. 1. f. 2. 
Ostrea lsevis. Linn. Trans, viii. pi. 3. f. 5. 
Shell somewhat orbicular or inclining to oblong, with 
fiat equal valves, yellowish or purplish-brown, often mar¬ 
bled rayed or streaked with paler or darker colors ; the 
surface sometimes quite plain, or with a few obscure trans¬ 
verse wrinkles, but more generally marked on the lower 
part with numerous rounded ribs, a smaller or greater 
number of which are frequently more prominent and 
placed at unequal distances 5 and sometimes the upper 
plain department i 3 separated from the marginal ribbed 
part by a strong depressed transverse line, the whole sur¬ 
face being always marked with very numerous and most 
minute longitudinal lines, which run rather obliquely to¬ 
wards the sides, and are crossed by as fine transverse ones, 
giving it a kind of shagreened appearance under a glass : 
ears unequal; the larger one with four or five strong 
transverse ribs, and crossed by longitudinal transverse 
wrinkles; the other very small j inside glossy, yellowish 
or rich purple, finely striate longitudinally, with the mar^ 
gin slightly notched: length an inch; breadth not quite so 
much. 
West of England, Scotland, and Dublin bay: v. m. 
B. JVithout cars, and the surface generally rough and 
uneven. Oyster 13, 14. 
12. Ostrea edulis. Common Oyster. 
Lister, pi. 193, and 194— Pennant , pi. 65, lower fig.— 
Da Costa, pi. 11. f. 6—Dorset Cat. pi. 11. f. 6—Lmn. 
• Trans, vi. pi. 18. f. 9, 10. 
Shell more or less orbicular, but subject to much varia¬ 
tion of form size and bulk, often distorted and misshapen, 
n rugged 
