34 



description. The figures of the first division denote the space between 

 the lid and the opening ; those of the second the diameter of the opening ; 

 those of the third the depth of the boxes from the lower edge of the 

 opening to the deepest point of the nest trough ; and those of the fourth 

 the thickness of the bottom. 



The following are the measurements in millimetres of the diameters 

 of the inside of the nesting-cavities at the various points as indicated 

 in the above diagram : 

 Nesting-Boxes 



Size A. Al. B. C. D. 



At A. 60-65 60-65 80-85 

 B. 70-80 70-80 85-95 



C. 85-95 [ 85-95 115-125 160-180 160-180 



