THE ^PYOENIS. 489 



otlier species. Botli parents unite in providing food for the 

 young." 



In this narrative two points are especially worthy of notice. 

 In the first place, the egg of the Cow-bird is proportionate in size 

 to the bird which laid it. Now, one of the most remarkable facts 

 connected with the history of the common cuckoo is, that al- 

 though the bird is as large as a small hawk, its egg is scarcely 

 half as large as that of a thrush or blackbird, as indeed is needful 

 for its admission into the nest of a hedge sparrow or redstart. 



Here, then, we have an example of a bird laying an egg which 

 is extremely small in proportion to its own size, while in the ap- 

 teryx, or kiwi-kiwi of New Zealand, we have an example of a 

 bird laying an egg which is absolutely gigantic in proportion to 

 its own size. The apteryx is not a large bird, certainly not larger 

 than a Gruinea-fowl, and yet its egg looks like that of a swan, and 

 weighs just one quarter as much as the bird which produced it. 

 Thus it is evident that the dimensions of an egg afford no cer- 

 tain criterion respecting .the size of the bird that laid it ; and al- 

 though a large bird usually lays a large egg, and a small bird 

 lays a little one, the cases may be reversed, as in the instance just 

 mentioned. 



All naturalists are familiar with the gigantic egg laid by some 

 bird unknown, and called by the provisional name of JEpyornis, 

 or " tall bird." This egg makes that of the ostrich itself shrink 

 into insignificance, for its lineal measurement is precisely double 

 that of a large ostrich egg, and its cubic bulk is eight times as 

 great. In fact, the sepyornis egg looks as gigantic by the side of 

 an ostrich egg as does an ostrich egg near that of a duck. It was 

 therefore imagined that the aspyornis must be at least eight times 

 as large as the ostrich, and a height of sixteen feet was attributed 

 to the unknown bird. 



Now it is easy to work out this problem by the rule of three, 

 and to give the result in figures ; but when that result is com- 

 pared with existing facts, it becomes startling. On paper, a height 

 of sixteen feet for an ostrich-like bird seems rather gigantic, but 

 does not appear to carry with it any idea of its real magnitude. 

 The height of a very fine ostrich being about seven or eight feet, 

 we say that the sepyornis must be twice as tall as an ostrich, and 

 so dismiss the subject from our minds. But when we come to 

 compare the imaginary bird with actually existing beings, we 

 shall better understand the dimensions of a bird that measured 



