CV I'SKLID.K - THE SWIFTS. 



421 



Family CYPSELIDJE. — Tun Swifts. 



Ghak. Bill very smiii! without iiot(!li, triangular, much broader than high ; the cnhucn 

 not one sixth the gape. Anterior toes cleft to the base, each with three joints, (in the 

 typical species,) ond covered with skin or feathers ; tin.' middle (?lnw witho\it any scn-atioiis ; 

 tlic lateral toes nearly equal to the middle, llill without bristles, but with minute feathers 

 extending along the under margin of the nostrils. Tail-feathers ten. Nostrils elon>;ated, 

 superior, and very close together. Plumage compact. Primaries ten, elongated, i'alcate. 



The Cypsdidcc, or Swifts, are Swallow-like birds, generally of nither tliill 

 phuuage and medium size. Tliey were formerly associated with tlie true 

 Swallows on accomit of their small, deeply cleft bill, wide gape, short feet, 

 and long wings, but are very difl'ereut in all the essentials of structure, 

 belonging, indeed, to a difl'erent order or suborder. The bill is much smaller 

 and shorter ; the edges greatly inflected ; tlie nostrils superior, instead of 

 lateral, aid witliout bristles. The wing is more falcate, with ten primaries 

 instead of nine. The tail has ten feathers instead of twelve. The feet are 

 weaker, without distinct scutelhe ; the hind toe is more or less versatile, the 

 anterior toes fretiuently lack the normal nnmber of joints, and there arc 

 other features which clearly justify the wide separation here given, especially 

 the difference in the vocal organs. Strange as the statement may be, tlu'ir 

 nearest relatives are the Trochilidcc, or Humiuing-Birds, notAvithstanding 

 the bills of the two are as opposite in shape as can readily be conceived. 

 The sternum of the Ci/pselida: is also very ditierent from that of the Ilirun- 

 dinida;, as will be shown by the accompanying figure. There are no emargi- 



OuBtura prtagiea. 



Pro^f snbh. 



The 

 The 



natipns or openings in the posterior edge, which is regularly curved, 

 keel rises high, for the attachment of the powerful pectoral muscles, 

 manubrium is almost entirely wanting. 



In this family, as in the Caprimnlgida:, we find deviations in certain 

 forms from the normal number of phalanges to the toes, which serve to 

 divide it into two sections. In one, the Clutturinw, these are 2, 3, 4, and 5, as 



