276 THE WORLD OF LIFE CHAP. 



that render the world of life an inexpressible delight to all 

 who have been led to observe, to appreciate, or to study it. 

 It is through the action of some such internal selecting 

 agency that we owe much of what we must call the 

 charming eccentricity of nature of those exuberances of 

 growth which cause the nature-lover to perpetually exclaim, 

 " What can be the use of this ? " In the birds-of-paradise 

 we had long known of the tail-feathers, the breast-shields, 

 the masses of plumage from under the wings, the crests, the 

 neck-tippets, all in wonderful variety of shape and colour. 

 Then, in the island of Batchian I obtained a bird in which 

 from the bend of the wing (corresponding to our wrist) there 

 spring two slender and flexible white feathers on each side 

 standing out from the wing during flight, whence it has 

 been termed the standard-winged bird-of-paradise. Again, 

 a few years ago, there was discovered in the mountains of 

 German New Guinea another quite new type, in which, 

 from the corner of each eye, a long plume arises more than 

 twice the length of the bird's body, and having, on one side 

 only of the midrib, a series of leaf-shaped thin horny plates 

 of a beautiful light -blue colour on the upper surface, 

 contrasting in a striking manner with the purple black, 

 ochre yellow, and rusty red of the rest of the plumage. 



In the comparatively small number of birds-of-paradise 

 now known, we have a series of strange ornamental plumes 

 which in their shape, their size, their colours, and their point 

 of origin on the bird, exhibit more variety than is found in 

 any other family of birds, or perhaps in all other known 

 birds ; and we can now better explain this by the assistance 

 of Weismann's law in a highly dominant group inhabiting 

 a region which is strikingly deficient in animals which are 

 inimical to bird-life in a densely forest-clad country. 



To this same principle we must, I think, impute that 

 superfluity of dazzling colour in many birds, but more especi- 

 ally in many insects, in which it so often seems to go far 

 beyond usefulness for purposes of recognition, or as a warning, 

 or a distracting dazzle to an attacking enemy. 



Even in the vegetable kingdom this same law may have 

 acted in the production of enormous masses of flowers or of 

 fruits, far beyond the needful purpose of perpetuating the 



