296 THE STORY OF THE BIRDS 



the species to which the male may belong. 

 Here again, however, we are in the dark, and 

 the subject is one fraught with interest, and its 

 study is likely to yield results of great value. 



We have now to consider the more philoso- 

 phical portion of the subject of eggs. Here, as 

 we found to be the case with nests, the won- 

 drous beauty of these shells is purely a utilita- 

 rian one, and it behoves us then to inquire what 

 part these varied tints play in avine economy. 

 As we found that to a very great extent the 

 colour of the parent's plumage is correlated 

 with the manner of nidification and the style of 

 architecture, so in like manner shall we find a 

 similar relationship between the colour of the 

 eggs and the manner in which they are brought 

 to maturity. Here again, in order to under- 

 stand the facts, it will be necessary to divide 

 eggs into groups quite irrespective of the taxo- 

 nomic affinities of the species that produce them, 

 but according to whether they are adorned with 

 colour pigments or not. 



Taking into consideration the important fact 

 that Birds and Reptiles have descended from 

 some common ancestral type, we are probably 

 correct in the assumption that the eggs of the 

 earliest avine forms were devoid of any of those 



