Order VI. MACROCHIRES. 



The families of Swifts, Nightjars, and Frogmouths, here classed 

 together, afford an even more difficult case than that of the 

 Amsodactyli, their differences being of so well-marked and 

 important a character as to make it very doubtful whether they 

 can belong to the same order. The hallux in all is connected 

 with the fiexor 'perforans cliffitonim, and the arrangement of the 

 deep flexors (except in Macropteryx) is Galline, as in Coracias and 

 Buceros; the oil-gland is nude or wanting, the manubrium sterni 

 very small or absent, the coracoids separate, and the number of 

 both primary-quills and tail-feathers 10. The spinal feather- 

 tract is well-defined on the neck, but forked on the upper back. 

 All, too, have a short bill and an excessively broad gape, and all 

 live on insects captured in the air. 



The three families Cypselidcv, Caprimulgido!, and Podargidce 

 form suborders. 



The Trocliilida', or Humming-birds of America, are generally 

 placed in this order, but their relations to the Swifts are 

 disputed by a few naturalists. 



Another American family, Steatornithidce, appears probably 

 allied to the Podargidce. 



The other suborders are all Indian, and may be thus dis- 

 tinguished : — 



a. Palate segithognathous ; no basipterygoid pro- 

 cesses ; no caeca ; a nude oil-gland Cypseli. 



h. Palate schizognathous ; basipterygoid pro- 

 cesses present ; caeca functional ; a nude 

 oil-gland Caprimulgi. 



c. Palate desmognathous ; no basipterygoid pro- 

 cesses ; caeca large ; no oil-gland ; a powder- 

 down patch on each side of the rump .... Podaegi. 



Suborder CYPSELI. 



No caeca. Oil-gland present, but nude. Palate segithognathous ; 

 no basipterygoid processes. No median wing-coverts. Sternum 

 without posterior incisions, the keel high. No semitendinosus 

 muscle. A large aftershaft. 



