CY PSKLID.K - TIIK SWIFTS. 



421 



Family CYPSELIDJE. — The Swifts. 



CiiAK. Bill vory small, without noU-i). trian^'ular, much hrojulor thnn hi^'h ; tlu' culmni 

 not out' sixth th«? j^ajw. Auterior toes (.'left to the bus«', ea<h with three joints, (in the 

 typical s|K'«'it's,) auil covered with skin or feathers ; tin? middle claw without any serrations ; 

 the lateral toes nearly equal tu the niidille. liill without bristles, hut with minute feathers 

 extendinjif alo!ig the under margin of the nostrils. Tail-feathers ten. Nostrils elon^Mti-d, 

 su|»erior, and very close together. Plumage compact. Primaries ten, elongated, fakate. 



The Cypselidft, or Swifts, are Swallow-like birds, generally of mther dull 

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

 Swallows on account of their small, deeply cleft bill, wide gape, slujrt feet, 

 and long wings, but are very different in all the essentials of structure, 

 belonging, indeed, to a different order or sul)order. The bill is much smaller 

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

 lateral, and without 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 vereatile, the 

 anterior toes frequently lack the normal number of joints, and there are 

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

 the difterence in the vocal organs. Strange as the statement may be, thfir 

 nearest relatives are the TrochilUlcc, or Humming-Birds, notwithstanding 

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

 The sternum of the Ci/pselidm is also very different from that of the Hirun- 

 diiiidce, as will be shown by the accompanying figura There are no emargi- 



Chatura ptla^a. 



Progne subis. 



nations or openings in the posterior edge, which is regularly curved. The 

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

 manubrium is almost entirely wanting. 



In this family, as in the CaprimuJgidcc, 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 Clvceturincc, these are 2, 3, 4, and 5, as 



