SWIFT 



429 



sentatives. In many structural points the two groups are undoubtedly 

 very unlike ; but it is, nevertheless, a most remarkable circumstance 

 that the bones of the palate are constructed in both swallows and 

 swifts on the same type, and that no other picarian birds display a 

 similar arrangement in this region of the skull. According to the 

 classification here followed, the swifts are placed in the same ordinal 

 group as the nightjars, of which they form a family (Cypselidai) 

 differing structurally from the Caprimulgidai in the arrangement of the 

 bones of the palate, and in the possession of distinct blind appendages 

 (caica) to the intestine. 



To point out in detail the resemblances and differences between 

 swifts and other 

 picarian birds on the 

 one hand, and be- 

 tween the former and 

 swallows on the 

 other, will, however, 

 be quite unnecessary 

 on the present occa- 

 sion, and it will 

 suffice to point out 

 a few of the leading 

 characteristics of the 

 group under con- 

 sideration. In the 

 air swifts may be re- 

 cognised at a glance swift. 

 by their remarkable 



resemblance in shape to a cross-bow. The short beak is hooked at the 

 tip, and has a very wide gape ; the wings are of great length, with the 

 primary quills unusually large and distinctly curved, but the secondaries 

 very short ; while the feet are small and weak, with the first, or hind 

 toe, more or less reversible, and in the more typical species all four toes 

 capable of being turned forwards. In the skeleton a noticeable feature 

 is the extreme shortness of the humerus, or upper bone of the wing, 

 which is remarkably different from the corresponding bone of the 

 swallciw ; the breast-bone, or sternum, also differs from that of the 

 swallow in the absence of any notch on its hind, or lower border, as 

 well as in its great length and the excessive depth of the central keel. 

 Another, but less important, difference between swifts and swallows 

 is the presence of only ten tail-feathers in the former against twelve 



MOUNTED IN THE ROW 



