348 
THE OCEAN WORLD. 
of its white spots upon a bed of red and brown marble ; Fi<. 
II, & e 
Purple Pecten ; Fig. III., the Coral Peeten ; Fig. IV, the Tiger Pecten , 
Fig. V, the Foliaceous Pecten ; and Fig. VI, the Northern Pecten. 
The animal which inhabits the Pecten shell has the general f° lJI1 
of the oyster, differing however from it in a remarkable mann® 1 '' 
The edges of the mantle arc furnished with multiplied fringes of simp; 
tentacles, between which we find other tentacular appendages a m ^ 
thicker, each terminating in a sort of small pearl, vividly colon? 6 ’ 
to which is attached a nervous thread, which has been taken for ,lU 
eye. Another difference : the branchiae, in place of being conm 
.eM 
by a striated lamina, as is the case in the oyster, are cut into para- 
ng 
capillary filaments, forming a tree and floating fringe, and the m° u 
is surrounded by salient many-cleft lips 
.tli 
While the oyster shell is completely fixed to its bed, the Pecten 
is, 
o» 
in 
the contrary, perfectly free, and shifts from place to place, moving ^ 
the water even with a certain amount of agility ; by smartly closing 1 ^ 
half-opened valves and forcibly expelling the water, it moves backwn 1 
by a sort of reaction ; this action, repeated many times, compels 
animal to move almost in spite of itself, and enables it to avoid dang® 1 ’ 
or directs its steps towards the spot it wishes to reach. Some natural 1 ^ 
even assert that, when raised to the surface, the Pecten half opens 
shell in such a manner t 11 
the upper valve serves 
purpose of a sail. 
The Pectens, of whi^ 1 
7 AP* 
hundred species are ^ 
scribed, are inhabitants 
every known sea. T^’ en 
to Em-of’ 
belon 
° mem 
species 
among which we may 
tion P. opercularis, rep r ^ 
sented in Fig. 130; 
habits European seas. ' 
137 represents the ^ 
mantled Pecten (P- p ‘ lC ’ 
Linn.) of the Indian 
and Fig. 138, the Concentric Pecten (P. Japonica ) of the J a P 
Fig. 136. Pecten opercularis (Linnaeus). 
seas. 
