VERTEBRATA: AVES. 



623 



being more especially adapted to the delicate labours of nidi- 

 fication, have neither the webbed structure of those of the 

 Swimmers, nor the robust strength and destructive talons 

 which characterise the feet of the Birds of Rapine, nor yet the 

 extended toes which enable the Wader to walk safely over 

 marshy soils and tread lightly on the floating leaves of aquatic 





Fig. 345. A, Head of Hoopoe ( Upupa epops), showing the Tenuirostral type of beak. 

 B, Head of Red-backed Shrike (Lanius collurio), showing the Dentirostral type of 

 beak, C, Head of White-bellied Swift (Cypselus inelbd)^ showing the Fissirostral 

 type of beak. D, Head of Corn-bunting {Einberiza iniliaria), showing the Coni- 

 rostral type of beak. E, Foot of the Yellow Wagtail (Mo tori Ha sulphured). F, 

 Foot of a Finch (Fringilld). 



plants ; but the toes are slender, flexible, and moderately 

 elongated, with long, pointed, and slightly curved claws. 



