OSTREADiE. 
325 
^ e ted to the rock or other submarine body, the point of adherence 
e * n g near the summit of the lower valve, at the part called the heel. 
Let us suppose the oyster opened by the double dissection of the 
%'ament of the central muscle and of the adductor valves. "When 
ls playecl before our eyes, we see in the bottom of the shell a flattened 
^Ltpeless animal, semi-transparent, greyish, and somewhat oval- 
8 haped. The gastronomist, who seldom sees beyond his nose, thinks 
ttiat in 8 pite of its culinary merits the oyster belongs to the lowest 
^k of animal existence ; but he deceives himself, aud does not know 
complex and delicate is the organization of the humble bivalve, 
be animal is enveloped in a sort of smooth, thin, contractile tissue 
Ca Ued the mantle, which folds round it, presenting two lobes, separated 
the greatest part of its circumference, and forming a sort of hood, 
be summit of which abuts upon the hinge of the bivalve. The edges 
this mantle are fringed with very small cilia, which the creature 
Catl extend and draw back at pleasure, and which seem to be gifted 
Wlt h a certain amount of sensibility. It is this mantle which secretes 
ailf l deposits the calcareous matter which forms the shell, each plate of 
"kick is an enlargement on the preceding one, until it constitutes a 
pyramid of thin convex lamellae. 
At the point where the lobes of the mantle meet, near the summit 
p Lie valve, is the mouth of the animal, with its thin membranous 
Ts. This organ is large and dilatable, and is accompanied by four 
triangular pieces, by means of which the animal introduces its 
IJ0( into the stomachal cavity. 
A very short gullet is attached to the mouth, which leads to a 
L-iir-shaped stomach. After this stomach comes a slender sinuous 
jbtestine, which, leading obliquely towards the anterior, descends a 
e > then reascends, passes behind the stomachal cavity, nearly on 
eve l with the mouth, crossing its first path in order to reach the 
Post, 
ter 
,er ior face of the adductor muscle, in the centre of which it 
^’minates with a free opening. The stomach and intestines are 
bounded on all sides by the liver, which alone constitutes a notable 
° r Lou of the mass of organs. This liver is of a blackish colour, 
P er Vaded with a deep yellow liquid, which is the bile. Thus the 
°Qiack and intestines of the oyster are surrounded by the liver ; the 
bioutk 
is connected with the stomach, and the intestines open in the 
