A PRACTICAL HANDBOOK OF 

 BRITISH BIRDS- 



VOL. II. 



Order CYPSELI. 



This Order consists of the Swifts only. Three subfamilies are 

 generally recognized, but two only are represented in Europe, the 

 third being entirely tropical and oriental, and now often looked 

 upon as a distinct family. 



Palate segithognathous ; cervical vertebrae 13 or 14 ; basi- 

 pterygoid processes absent ; humerus very short ; ambiens muscle 

 absent ; sternum with short spina externa and interna ; phalanges 

 (digit-bones) of middle and outer toe in many cases reduced. 

 Ten primaries, the first longest ; wings very long and pointed, 

 secondaries short. Always ten rectrices. Gape very wide, bill 

 small. Feet short and strong, hind-toe more or less reversible. 

 Salivary glands strongly developed and very active during nesting 

 season. Skin very strong. Palsearctic species migratory. Eggs 

 usually two, white unspotted. The most aerial birds ; young 

 helpless and blind. 



Family CYPSELID^ (APODID.E). 



Characters same as those of Order Cypseli. 



Key to subfamilies and genera of family Cypselid^: (ApoDiDiE). 



Outer and middle toe with only three phalanges, tarsus thickly feathered, 



tail without spines Cypselince (Apodince) 



(Genus Apus) 



Outer and middle toe with more than three phalanges, tarsus bare, 

 tail with spines, formed by shafts of rectrices being elongated beyond 



end of webs Chceturinos 



(Genus Chcetura) 



VOL. II. B 



