may be made at a small cost. This consists of a box with a wooden bottom and perforated zinc sides which are supported by a stout wooden frame.

Beyond these boxes all that are required are some perforated zinc hatching trays. These should be 1½ inches deep. They are very easily made, and the ova hatch out well in them. Though ova sometimes hatch out very successfully even when piled up in two or three layers, it is safer to have them in a single layer. The trays should be suspended in the boxes, and the boxes in the ponds close to the inlets, so that a good current of water may flow through them. The bottom of the boxes should be covered with a thick layer of gravel, but the trays are to be used without gravel. It is advisable to have as much grass as possible round the ponds, and such trees as willows and alders should also be planted round them. Willows and alder sticks planted in the early part of the year come into leaf in the same spring, and afford shade to the young fish in the summer. Some suitable weeds should also be grown in the rearing ponds. Water-cress, water-celery, water-lobelia, starwort, and water-milfoil, are all good. They should be arranged, however, so as to prevent as much as possible the little fish finding hiding places, and it is for this reason also that I have recommended slightly sloping banks when the sides of the ponds are not made of cement. The weeds should be planted some time before the little fish are turned out of the boxes.

Finally, I must caution my readers again on one or two points before I leave the subject of the hatching trays, rearing boxes, and ponds. Enamel, varnish, or charr all woodwork thoroughly, leaving no speck of wood bare and no crack open. Let the water run through and over all your ponds and apparatus for as long as possible before you begin operations.

CHAPTER VI

TROUT. MANAGEMENT OF THE OVA AND ALEVINS

Everything should now be ready for the reception of the ova. The rearing boxes are resting upon stones placed at the bottom of the ponds, with the edges some six inches above the level of the water, and moored to the sides to prevent their being moved by the current. The hatching trays are suspended in the rearing boxes, or placed upon movable rests in the boxes, with their edges just above the level of the water.

Notice is usually sent a day or two before the ova are despatched from fish cultural establishments, so the amateur has no excuse for not being absolutely ready for their reception. They are packed in various ways, and nowadays suffer but little in the transit. The ova should always be carefully washed before they are placed in the hatching trays. Mr. Armistead, in A Handy Guide to Fish Culture, says:—"If just turned out of a packing case there may be small pieces of moss or other material amongst them. In any case a wash will do them no harm, and the process is a very simple one. Take a pail, half-filled with ova, and then fill up with water, and with a small lading-can lift some of the water out, and pour it back again, so as to cause a downward current, which will agitate the ova. Their specific gravity being greater than that of water, they immediately retire again to the bottom of the pail, and by at once pouring off as much water as is practicable, any floating particles of moss, etc., may be carried off. Should any be left, the process should be repeated, and it may even be necessary to repeat it several times. When all is right take a ladle, or small vessel of some kind, say a good-sized tea-cup, and gently ladle out the eggs, and place them roughly on the grills, where they may be roughly spread by means of a feather."

To these instructions I would add some for the amateur, who will probably deal with a comparatively small number of ova. The ova should be washed in some large vessel full of water in the manner above described. When the water is quite clear, and the ova clean, they may be caught in mid-water as they are sinking either in the hatching trays or in a cup. If caught in a cup they should be transferred with great care to the hatching trays, and spread out in a single and somewhat spare layer. They must on no account be poured into the trays from a height. While under water well-eyed ova will stand a good deal of gentle tumbling about, but if dropped into the water from even a little height the concussion is likely to kill them.

Mr. Armistead recommends glass grills rather than trays such as I have described, but I have found the trays work very well, and they are very simple and clean. Glass grills are, however, very excellent, though they necessitate a somewhat greater initial outlay than do the perforated zinc trays.

A German fish culturist has recently recommended keeping a stock of fresh-water shrimps (Gammarus pulex) in the hatching trays and rearing boxes. He says that the shrimps eat only the dead ova, and never touch the living ones. They also eat any vegetable or animal débris. I have never tried the experiment myself, and so cannot speak from experience.

Dead ova should be always removed at once, and the hatching trays should be gone over carefully once or twice a day to see if any are present in them. Dead ova are easily recognized from the fact that they become opaque and white. They are best removed with a glass tube. The thumb is placed over one end of the tube, and the other end brought directly over the dead ovum. When the thumb is removed from the end of the tube held in the hand the water will rush up into the tube, carrying with it the dead ovum. The thumb is then replaced over the end of the tube, which is lifted from the water with the ovum retained in it. This tube may also be used for removing any extraneous bodies which may get into the trays or boxes.

A form of fungus known as Byssus grows upon dead ova, and it is principally for this reason that they must be removed. Livingstone Stone says of Byssus:—"With trout eggs in water at 40° or 50° Fahrenheit, it generally appears within forty-eight hours after the egg turns white, and often sooner, and the warmer the water the quicker it comes. It is never quite safe to leave the dead eggs over twenty-four hours in the hatching boxes. The peculiarity of Byssus is that it stretches out its long, slender arms, which grow rapidly over everything within its reach. This makes it peculiarly mischievous, for it will sometimes clasp a dozen or even twenty eggs in its Briarean grasp before it is discovered, and any egg that it has seized has received its death warrant." Mr. Armistead has known it appear within twenty-four hours. Byssus develops only on dead ova.

Saprolegnia, known to fish culturists as "fungus," attacks both living or dead ova. If the woodwork is properly varnished or charred, and the ova managed thoroughly, there should, however, be but little risk of fungus. Light is favourable to the growth of fungus, and, therefore, wooden lids should be placed over the rearing boxes. These should be kept partially on after the young fish have hatched out, and be replaced by covers of fine wire netting spread on closely-fitting frames, when the fry have begun to feed. These obviate the necessity of covering up the ponds during the first stages.

Many small creatures such as caddis-worms will eat the ova, and therefore a careful watch should be kept upon the hatching trays as it is marvellous how such creatures find their way in, in spite of all