38 Bird-Song : and New Zealand Song Birds 
the variation in nest-building' has not, so far as I know, been 
recorded. 
Another variation in eggs has been observed. It was noted 
through a child sending a hen’s double-egg as a curiosity 
Hens’ and ducks’ double eggs came in from all over the islands • 
—double, that is, in having one shelled egg inside the other 
One (a hen’s) was ten inches in circumference one way, eight 
inches the other, and both eggs were perfect, with shell, white 
and yolk. Some of these eggs were imperfect in that one egg 
might be soft-shelled, or contain white only, or yolk only; 
some were double in that two perfect soft-shelled eggs were 
joined together with a pipe. A hen’s triple egg was recorded, 
the outer egg being twice the ordinary size, and containing 
both white and yolk: the second egg was hard-shelled, like the 
outer, and contained white, but no yolk; the third or inner 
egg, which was about the size of a blackbird’s egg, was soft- 
shelled, and contained white, but no yolk, like the second. One 
duck’s quadruple egg w r as found. It was nearly twice the size 
of an ordinary egg, having a beautifully tinted shell, very 
translucent. The outside egg and the second and third con¬ 
tained white only; but the fourth and innermost egg, about the 
size of a small cherry, contained white and yolk,—the only 
perfect egg of the four. Of small birds, a starling’s double¬ 
egg was sent to me, both eggs hard-shelled. A blackbird’s 
was found, the outer egg containing white and yolk, the inner 
two yolks but no white. 
Now the question arose, would any of these eggs, if perfect, 
hatch out? There seemed to be no way of discovering this, 
as an egg could only be known for certain to be double by 
breaking it. One man told me that as a boy he used to collect 
eggs and breed canaries, and that on one occasion a hen sat 
on four eggs and brought out five young ones—but he thought 
someone had played a joke on him. One day, however, another 
canarv-breeder brought an egg, which had evidently been a 
double-yolked egg, and it contained two dead chicks. He said 
it had been so long hatching that he broke it to see what was 
wrong, and found the dead chicks. Evidently double-yolked 
