198 THE WORLD OF THE SEA. 
three or four rows. These cilia possess some sensibility, for the 
creature can extend them at will. 
If the folds of the mantle’ which are in front of the oyster 
be raised up, at the crease of their junction will be found four _ 
irregular triangular plates, close together and surrounding an 
opening. These are the /fs, and the opening is the mouth. These 
plates are the tentacule of the oyster—they choose its food, and 
introduce it into the mouth, the cils doubtless causing currents of 
water to flow past them, which bring the nourishment within their 
reach. The mouth itself seems to be large and dilatable, and 
opens directly into the stomach, which is a pear-shaped, cylindrical 
pouch. From the other extremity of the stomach a fine sinuous 
intestine takes its rise, which passes obliquely towards the back 
of the creature, descends slightly, then reascending, passes behind 
the stomachal cavity, and finally issues in the centre of the 
adductor muscle. The stomach and the intestine are surrounded 
on all sides by the ver, which is a dark-coloured body, permeated 
by a yellow liquid—the Jdz/e. 
Thus we may say that oysters have their stomach and intestine 
in the liver, the mouth upon the stomach, and the opening of the 
intestine in the back. 
It has long been the opinion that the most tasty part of the 
bivalve is the cushion, or quadrangular pad. Certain distinguished 
amateurs have proclaimed the principle of dividing the body of 
the creature transversely, and eating that part only. Natural 
history explains this gastronomical discovery—it shows that the 
bile, secreted by the liver, is contained in this substance; that it 
accelerates while it exhausts the tasting organs on the surface of 
the tongue and palate, aiding also the functions of’ the stomach. 
Beneath the liver is the Aeart—for oysters have a heart— 
which contains two distinct cavities, an auricle and a ventricle. 
The first is nearly square, its walls are thick, and of a dark brown; 
the second has the shape of a little pear, its tegument is not so 
firm as that of the auricle, and its colour is grey. The two 
anterior angles of the auricle each receive a great vessel. Each 
of these is formed by the union of three other smaller veins. 
From the point of the ventricle issues a canal, which soon divides 
into three divergent branches. One of them is directed towards 
