52 PECTINID A. 
are pure white on both surfaces. The membranous marginal 
areas of the mantle are elegantly arranged in meandering 
lines of pale red, brown and yellow, forming various-shaped 
lozenges. When the valves are opened, and the mottled 
surfaces of the double margins of each valve are in conjunc- 
tion, and the various circles of filaments and cirrhi fully ex- 
serted in a shallow basin of sea-water, it is scarcely possible 
to conceive a more beautiful and imteresting appearance. 
There are two rows of sea-green ocelli relieved at one part of 
the circle by a black pomt, with the pearly pupils deeply 
sunk in their hollows; there is usually a large eye under 
each rib of the shell; the others are much smaller, deposited 
in a row under them; they all amount to about thirty to 
thirty-five. The branchiz are small for so large a species ; 
there are a pair of palpi on each side, pale drab or brown, 
laterally attached, folding on each other, subquadrangular, 
composed of twelve to fifteen strands pectinated on both sur- 
faces, but more intensely on the mner; the buccal fringes are 
two rows of very bright red, well-foliated and branched fillets, 
which connect the palpi; the mouth is in the centre of them. 
The body, and the ovarium amalgamated with it, are of very 
small volume and usually white. The foot is snow-white, 
short, grooved, with a spatulate extremity. The liver is quite 
dorsal, black-brown, or an intense dark green. The brown 
suboval secreting glands on each side are as conspicuous in 
Pecten as in Ostrea. 
We may observe, that in all the Pectines the mass of the 
organs is small, and appears scarcely commensurate with the 
area of the shell; perhaps the deficiency is made up by the 
mantellar extensible margins and cirrhi, which coast the pe- 
riphery, bemg only interrupted by the very short ligamental 
area, from which point, on each side, they gradually increase 
in width and size to the centre of the aperture. The animal 
can effect a rapid progression by flappmg together the valves, 
with the ventral margins in front and the flat valve upper- 
most. 
This elegant and edible species, the Prince of the British 
Pectines, is frequently taken in the coralline zone at Exmouth. 
