106 



STRUCTURE AND CLASSIFICATION OF BIRDS 



I have italicised in the above list those groups which 

 come near to the supposed primitive condition ; and it will 

 be observed that those groups which are italicised are enough 

 to account for the ancestry of the rest. The main difficulty 

 is perhaps presented by the Cuculi ; but it may well be that 

 that group will ultimately prove to have a simple intestinal 

 tract. It will be observed also that the groups in question 

 comprise representatives of all the five large divisions of 

 existing birds admitted by GADOW, and of all the corre- 

 spondingly large divisions of FUEBEINGEE. Incidentally, 

 therefore, I find myself in reassuring agreement with those 

 authorities. In the systematic part of this work I have to 

 some extent discussed the mutual affinities of these different 

 groups. 



