ARTIFICIAL PROPAGATION 185 



The eggs arc set uniformly in rows conform to the glass tubes (just 

 as golf balls are in a rack), and each egg is plainly exposed to view 

 making supervision very simple and easy. 



The " baskets " used in the basket system of hatching are carefully 

 made of finely and closely perforated zinc sheets, and two rows of eight 

 baskets occupy the available space in each hatching box (see box 

 marked XI on plan), each basket being 9 in. long, 8 in. broad and 3 in. 

 deep (see basket marked F in box marked XI on plan). The whole 

 sixteen baskets rest upon the longitudinal side ledges and central runner 

 already described, at such a level that at least three-quarters of an inch 

 of water will flow freely over three layers of eggs. When it is added 

 that, as in the upper boxes, a strainer is placed at the intake and a screen 

 at the outflow, enough has been said to give an idea of the various 

 fittings of both systems, save in one particular. In discussing the 

 relative merits of the two systems I shall show that the basket system 

 requires a greater delivery of oxygen-laden water to the ova, therefore, 

 at Luss, we had to supplement the water handed on, say from box 

 No. V to box No. XI, in the lower tier by an independent connection 

 with the main inside the hatchery. From a pipe with stop-cock 

 (marked G on plan) there is fitted within the upper inner edge, and 

 branching along each side, of the box throughout its length, block tin 

 tubing perforated with needle points about one half-inch apart. When 

 the water at stop-coek G is turned on it is thrown from the perforations 

 of the right-hand tubing to the left-hand row of baskets, and from the 

 left-hand tubing to the right-hand row — a continuous spray bath being 

 thus given to the eggs all along the hatching box. It is a very simple, 

 very neat, and very effective arrangement. 



The eggs by this system are massed in the baskets one, two or even 

 three layers deep. 



It is a matter of some little practical importance — as well as of 

 interest — to know the relative hatching capacity of glass grilles and 



