There has hitherto been a fixed period for the annual sacrifice to crustacean gastronomy. As my readers are already aware, there is a well-known time for the supplying of oysters, which is fixed by law, and which begins in August and ends in April. During the _r_-less months oysters are less wholesome than in the colder weather. The season for lobsters begins about March, and is supposed to close with September, so that in the round of the year we have always some kind of shell-fish delicacy to feast upon. Were a little more attention devoted to the economy of our fisheries, we might have lobsters and crabs upon our tables all the year round. In my opinion lobsters are as good for food in the winter time as during the months in which they are most in demand. It may be hoped that we shall get to understand all this much better by and by, for at present we are sadly ignorant of the natural economy of these, and indeed all other denizens of the deep. A new branch of shell-fishing has been lately revived in Scotland. I allude to the pearl-fisheries which are now being carried on in our large streams, and which, if prudently conducted, may become a source of considerable wealth to the Scottish people. The pearl is found in a species of shell-fish which is a variety of the mussel, not an oyster, as is commonly supposed. The pearl has been pronounced the most beautiful of all our gems, coming, as it does, finished and perfect, direct from the laboratory of nature, and consequently owing nothing to the cunning of man except its discovery— “Ocean’s gem, the purest Of Nature’s works! what days of weary journeyings, What sleepless nights, what toils on land and sea, Are borne by men to gain thee!” In the Eastern seas professional divers are employed to go down into the depths of the ocean in order to obtain them—a dangerous occupation, at one time only followed by condemned criminals. The best-known fishery for pearls is that at Ceylon, which was a very lucrative concern, at one time, in the hands of the industrious Dutch. [Illustration: THE SCOTTISH PEARL-MUSSEL.]