TtOW YOtTXG fclRT)S HrEaK THE EGG SHELL, 



'247 



evolution of birds and now no known birds have true teeth. So obvious 

 *i this fact that we often hear the expression, "As rare as hens" teeth". 

 To be sure ducks and geese have peculiar serrations on the edges of both mandi- 

 bles, (see fig, 117 and 118) but these are not true teeth, simply horny projec- 

 tions from the biii. 



Returning to young birds we find that they have, at least, two ways of 

 breaking the shell, these methods varying with the species; If we examine 



Fig. 118. 



Head of Barnacle Goose-. 



=a newly-hatched chicken or the newly-hatched young of almost all land biicta, 

 We shall find on the tip of the upper mandible of the bill a little pointed tooth 

 •developed which is very hard, being, in fact, apparently ccmposcd of limy 

 material. It is with this tooth that the young chick breaks the sstadl by 



