THE OYSTER. 



greenish -grey colour. Its figure bears a rude resem- 

 blance to an oval, whose smaller eud lias been truncated. 

 Tlie truncated portion answers to the flesh of the oyster, 

 and represents the top of the shell. The curved line 

 springing to the left forms its anterior portion ; that on 

 the right, which is less rounded, represents its posterior 

 region, or back ; and the thick end of the oval its 

 inferior portion. On the summit of the animal may be 

 perceived a bod}- resembling a small and irregular four- 

 sided cushion, lightly swollen. 



The oyster is clothed with a very simple, thin, 

 smooth, contractile manlle, which folds back on itself, 

 and possesses a couple of tubes, separated for the 

 greater part of its circumference; that is, in fiont, at 

 the larger end of the oval, and behind, towards the 

 inferior portion. This mantle may be compared to a 

 kind of hood, very much compressed, and with its 

 uppermost side turned towards the tlesh. The edges 

 of this tunic are somewhat thick, and fringed inside 

 with a multitude of tiny cilite, while outside they are 

 also arranged in three or four rows, like a closely- 

 woven border. The cilise are gifted with a lively 

 sensibility, and the animal can lengthen and shorten 

 them at its pleasure. 



If we divide the lobes of the mouth in front, we 

 shall observe at their point of union, in the interior of 

 the fold, four smooth triangular pieces lying one against 

 another. These arc the parts of the animal charged 

 with the duty of selecting its food, and introducing it 

 into its mouth. They are called tentacles, or labial 

 pnpillie.. The mouth is situated in the centre; it is of 

 large size, capable of e.xpansion, and opens directlj' 

 into the stomach. The latter, in form, is like a cylin- 

 drical pouch ; it lies concealed in the interior of the 

 qnadrilatei'al cushion. From the hind part of the 

 stomach issues a thin sinuous intestine, which strikes off 

 obliipiely towards the anterior side, descends a little, 

 then reascends, passes behind the abdominal cavity, 

 descends towards the back, and terminates in a floating 

 canal or tube, whose extremity is shaped like a funnel. 

 Here we lind the opening through which the excre- 

 ments are ejected. 



The stomach and intestine are on every side sur- 

 roundedand compressed bya thick, blackish, and copious 

 matter, penetrated with a yellow fluid. This matter is 

 tlic liver ; the yellow liquid is the bile. 



Thus, then, we ma\' say, in brief, that the oyster has 

 its stomach and intestine in its liver, the opening of its 

 mouth on its stomach, and the opening of the intestine 

 on its back. 



For a long time our gastronomes asserted that the 

 quadrilateral cushion was the most savoury and stimu- 

 lant portion of the oyster ; and in the environs of 

 Cettc, where these molluscs attain a larger size, some 

 celebrated amateurs adopt and proclaim the principle 

 of dividing the body of the mollusc transversely, and 

 of eating only the cushion. Natural history has ex- 

 plained this little gastronomical discovery. It has 

 ascertained that it is the bile secreted by the liver, and 

 contained in its substance, wdiich stirs and excites the 

 gustative surface of our tongue and palate, and also 

 assists the digestive and absorbent functions of the 

 stomach. 



Below the liver appears the Iieart (for oysters have 

 a heart), composed of two distinct cavities, an auriclo 

 and a ventricle; the former nearly square, with thic; 

 sides, and of a blackish brown colour; the second 

 shaped like a small pear, with thin sides, and of a 

 greyish hue. Each of the two anterior angles of the 

 auricle receives a vessel, into which three canals open, 

 formed by the union of numerous veins. Fiom the 

 ventricle issues a canal which immediately divides 

 into three divergent branches; one carij-ing the blood 

 towards the mouth and tentacles, another towards the 

 liver, and the third distributing it among the iuforiur 

 and posterior parts of the mollusc. 



The heart closely surrounds, we maj- almost say, 

 embraces, the terminal part of the intestines, tlie 

 reetutn, in such wise that the latter seems actually to 

 penetrate the very middle of the noble organ. 



Tlie blood of the oyster is colourless. It arrives, 

 vivified, in the cavity of the auricle. The latter, con- 

 tracting, pours it into the ventricle. This cylindrical 

 pouch contracts in its turn, precipitates the blood into 

 the great vessel which comes from it, and spreads it 

 through the whole bod}'. 



Oysters breathe in the bosom of the waters. Nature 

 has endowed them with org.ans to separate from this 

 liquid the small quantity of air incoiporated with it. It 

 is the oxygen of that air which purifies and renews the 

 blood. The respiratory portions are two pairs of leaves 

 or branchiiE, curved like bows, and formed of a 

 double series of very fine and exceedingly compacted 

 canals, which are attached transversely and disposed 

 with great symmetry; thej' might be called the teelh 

 of a pretty comb. They lie concealed under the loose 

 edges of the mouth. They have their origin near 

 the tentacles, and terminate towards the centre of the 

 posterior portion. The outer one shorter than the 

 inner ones. 



Oysters, being acephalous molluscs — i.e., molluscs 

 without heads — have no brain ; its substitute is a small 

 whitish bi-lobed body, situated near the mouth. From 

 this body issue a couple of slender nerves embracing 

 the liver and the stomach, and abutting on another 

 inflated substance, of the same nature and the same 

 form, placed beneath these organs. The first-named 

 enlargement supplies nerves to the mouth and ten- 

 tacles ; the second, to the respiratory apparatus. 



Oysters are without the organs of sight, hearing, and 

 smell. That of touch is situated in the four tentacles 

 of the mouth ; that of taste is located around the latter 

 orifice, and, perhaps, on the inner surface of the interior 

 tentacles. It seems very obscure. 



Of all the shell-fish, the oyster, peihaps, possesses 

 the most confined and imperfect faculties. While ren- 

 dering them almost immovable in their station, while 

 ]iermanently imprisoning them in their shells, and, ns 

 we shall hereafter see, refusing them separate sexes. 

 Providence, it is obvious, could not endow them with 

 very numerous wants and desires, or with varied and 

 very ardent passions : it made them almost apathetic 

 and inert, living and digesting in a serene tranquillity 

 almost akin to inditVerence. Nevertheles.s, as these 

 molluscs are essentially social in their habits, and 

 generally consist of very extensive conimunilios, it is 



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