REARING 179 



trays with a layer of eggs on each are piled one upon 

 another in a box, and in this way the ova will reach 

 their destination uninjured after a journey of several 

 days. 



In packing eggs for shipment to the antipodes, 

 layers of live, damp moss are inserted between each 

 tray, and the later stages of development of the 

 embryo are lengthened, and the date of hatching 

 deferred, by the use of ice. The live moss, by 

 absorbing the carbonic acid given oif by the eyed 

 ova, enables them to take in fresh oxygen, without 

 which they would be suffocated, just as they would, 

 at this stage, be drowned in a few hours if put in a 

 small bottle of water and kept still. 



The toughness and vitality of the ova of the 

 Salmonidse after reaching the eyed stage are very 

 remarkable, and present a striking contrast to their 

 extreme delicacy throughout the whole of the pre- 

 ceding stages, except during the first few hours after 

 being taken. From day to day after the appearance 

 of the eyes, the colour of the embryo will grow darker 

 and its outlines more distinct, until at last you can 

 see it twitching in the shell as if struggling for liberty. 

 'The plot thickens,' and you are on the tiptoe of 

 expectation. The hatching time is now close at 

 hand, and you may expect any day to be rewarded 



N 3 



