As is well known, there is a period every year during which the oyster is not fished; and the reason why our English oyster-beds have not been ruined or exhausted by overfishing arises, among other causes, from this fact of there being a definite close-time assigned to the breeding of the mollusc. It would be well if the larger varieties of sea produce were equally protected; for it is sickening to observe the countless numbers of unseasonable fish that are from time to time brought to Billingsgate and other markets, and greedily purchased. The fact that oysters are supplied only during certain months in the year, and that the public have a general corresponding notion that they are totally unfit for wholesome eating during May, June, July, and August (those four wretched months which have not the letter “r” in their names), has been greatly in their favour. Had there been no period of rest, it is almost quite certain that oysters would long ago—I allude to the days when there was no system of cultivation—have become extinct, so great is the demand for this dainty mollusc. Oysters begin to sicken about the end of April, so that it is well that their grand rest commences in May. The shedding of the spawn continues during the whole of the hot months—not but that during that period there may be found supplies of healthy oysters, but, as a general rule, it is better that there should be a total cessation of the trade during the summer season, because were the beds disturbed by a search for the healthy oysters the spawn would be scattered and destroyed. Oysters do not leave their ova, like many other marine creatures, but incubate them in the folds of their mantle, and among the laminæ of their lungs. There the ova remain surrounded by mucous matter, which is necessary to their development, and within which they pass through the embryo state. The mass of ova, or “spat” as it is familiarly called, undergoes various changes in its colour, meanwhile losing its fluidity. This state indicates the near termination of the development and the sending forth of the embryo to an independent existence, for by this time the young oysters can live without the protection of the maternal organs. An eminent French pisciculturist says that the animated matter escaping from the adults on breeding-banks is like a thick mist being dispersed by the winds—the _spat_ is so scattered by the waves that only an imperceptible portion remains near the parent stock. All the rest is dissipated over the sea space; and if these myriads of animalculæ, tossed by the waves, do not meet with solid bodies to which they can attach themselves, their destruction is certain, for if they do not fall victims to the larger animals which prey upon them, they are unfortunate in not fixing upon the proper place for their thorough development.