Vol. XXXV.] 110 



with perhaps the most distinctive mouth of all^ by a lemur 

 and a cat. 



[Many other instances were given, which through lack of 

 space it is impossible to quote, but which seemed to 

 bear out Mr. Swynnerton^s theory on this subject. — Ed.] 



Mr. Stuart Baker, referring to the first part of Mr. 

 Swynnerton's paper, remarked that he thought Mr. Swyn- 

 nertou's experiments formed a most interesting basis for 

 further research, but that he personally did not place very 

 much weight on his theories. Although he had never made 

 any experiments with egg-eating animals and birds, he had 

 kept many such and had never noticed that they distin- 

 guished in any way between the eggs ofi'ered them. 



In refutation of the theory that the evolution of Cuckoos' 

 eggs was carried out by the elimination of those resembling 

 eggs which tasted best, and consequent survival of those 

 which were most nauseous, he gave instances showing that 

 such was not the case. He pointed out that some of the 

 most remarkable cases of evolution in Cuckoos' eggs at 

 present known had consisted merely of an alteration in 

 resemblance from one egg to another, though both of 

 these latter were, equally, very popular articles of diet 

 amongst most, if not all, of the enemies against which they 

 had to contend. He suggested that Mr. Swynnerton's 

 theory of evolution by elimination overlooked the fact 

 that Nature nearly always acted on the broadest lines. In 

 this particular case, the one ever-present danger was de- 

 tection by the foster-parent, whereas the chance of detection 

 by an enemy was considerably more remote. It was, 

 therefore, more profitable for Nature to eliminate individuals 

 which incurred the former danger rather than those which 

 incurred the latter. 



Again, Mr. Swynnerton's theory was self-contradictory, in 

 that it allowed the powers of discrimination to those birds 

 wliich preyed upon eggs and refused the same power to the 

 birds selected as foster-parents by the Cuckoos, If, as he 

 Ksuggested, the enemies could distinguish eggs by their sight, 



