BIRDS. 



71 



secretion of the oil-gland. I shall speak of two 

 families only. 



Family: Lamellirostra (Ducks). 



The inner margin of the beak is covered by skin, 

 thrown into transverse ridges or tooth-like projee- 



Fig. 43. — Crested and Little Crrebes (JPodiceps cristatus and minor), 



tions. Swimming feet (Fig. 44). Tolerably long 

 wings; remarkable powers of flight. Feathers soft. 

 These birds mostly afiect shallow fresh water, in 



