204 On the Subclass Coraciiformes. 



Leptosomus, with its powder-down patches like the Podargidse, 

 seems to have so many affinities with the Coraciidse that, in 

 the absence of information as to the condition of their young 

 at birth, I have not ventured to separate them. 



The Halcyones contain four families : — 



Todidce. — Halcyones with cseca and large tufts to the oil- 

 glands ; two notches on each side of the posterior margin of 

 the steruum. 



Momotida. — Halcyones with no cseca ; tufts of oil-gland 

 very small or absent ; one or both of the notches on each 

 side of the posterior margin of the sternum converted into 

 foramina. 



Coliidce. — Halcyones with neither central nor lateral bare 

 tracts on the breast. 



AlcedinidcB. — Halcyones with tufted oil-gland and no cseca ; 

 two notches on each side of the posterior margin of the 

 sternum ; well-defined central and lateral bare tracts on the 

 breast. 



The Coracise consist of seven families : — 



Cypselida. — Coracise with no cseca; all four toes directed 

 forwards. 



Caprimulffida. — Coracise with cseca and basipterygoid pro- 

 cesses ; dorsal vertebrse heterocoelous. 



SteatornithidcB. — Coracise with caeca and basipterygoid 

 processes ; dorsal vertebrse opisthocoelous. 



Podargidae . — Coracise with a powder-down patch on each 

 side of the rump ; ten rectrices ; no oil-gland. 



Lepiosomidce. — Coracise with a powder-down patch on each 

 side of the rump ; twelve rectrices ; nude oil-gland. 



Coraciidce. — Coracise with no powder-down patches ; no 

 basipterygoid processes ; well- developed cseca ; episternal 

 processes not perfected to receive the feet of the coracoids. 



Meropidce. — Coracise with the episternal process perforated 

 to receive the feet of the coracoids. 



The Bucerotes consist of only one family, the Bucerotidse. 



The importance of the character upon which I have ven- 

 tured to found the subclass Coraciiformes has been to some ex- 

 tent admitted by some American ornithologists (cf. Stejneger, 



