CYPSELID^: SWIFTS. 



455 



and southward, common. General habits and traits of a night-hawk, but the difference between 

 the two is obvious when they arc flying. Eggs 2, heavily veined and marbled, 1.20X 0.87- 



22. Family CYPSELID^ : Swifts. 



Fig. 296. Northern Black Cloud Swift, nat. size. (E. H. Fitch.) 



Fissirostral Picarice. : 

 Bill very small, flattened, 

 triangular when viewed 

 from above, with great 

 gape reaching below the 

 eyes ; unnotched, unbris- 

 tled, the gape about six 

 times as long as the cul 

 men. Nostrils exposed, 

 superior, nearer culmen 

 than commissure, the 

 frontal feathers tending to 

 reach forward under them. 

 Wings extremely loug, 

 thin, and pointed (fre- 

 quently as long as the 

 whole bird) ; the prima- 

 ries acute and somewhat 

 falcate ; the secondaries 

 extremely short (nine ?). 

 Tail of 10 rectrices, va- 

 riable in shape, often 

 mucronate. Feet small, 

 weak, the envelope rather 

 skinny than scaly ; tarsi 

 naked or feathered ; hind 

 toe frequently elevated, or 

 versatile, or permanently 

 turned sideways or even 

 forward; lateral toes near- 

 ly or quite as lung as 

 the middle; anterior toes 

 deeply cleft, the basal 

 phalanges e.xtremely short, 

 the penultimate very long, 

 the number of phalanges 

 frequently abnormal (2, 3, 

 3, 3, instead of 2, 3, 4, 5 ; 

 see p. 127, flg. 40) ; claws 

 sharp, curved, never pecti- 

 nate. Plumage compact, 

 usually sombre and whole- 

 colored, or only relieved 

 with white; sexes alike. 

 Sternum deep - keeled, 



