VERTEBRATA: AVES. 629 



external toe nearly as long as the middle one, to which it is 

 united nearly as far as the penultimate joint. In consequence 

 of this peculiar conformation of the toes, these families were 

 united by Cuvier into a single group under the name of 

 Syndactyli. 



The Caprimulgidce are intermediate between the Owls and 

 the Passerine Birds. Their plumage is lax and soft, and they 

 have a hawking flight. The eyes and ears are large, the feet 

 short and weak, and the gape of enormous size and bordered 

 by vibrissae. Amongst the more remarkable members of the 

 family may be mentioned the Whip-poor-will (Antrostomus 

 vociferus) of North America, the More-pork (Podargus Cuvieri) 

 of Australia, and the extraordinary Guacharo Bird (Steatornis 

 Caripensis) of the valley of Caripe in the West Indies. 



The Hirvndinid(Z have a wide gape, with few or no vibrissae, 

 the wings being very long and the feet short and weak. All 

 the Swallows feed upon insects, which they catch upon the 

 wing, and they have a cosmopolitan range. 



The Swifts (Cypselid<z\ though closely resembling the Swal- 

 lows in external appearance and mode of life, have little real 

 affinity to them. The gape is extremely wide ; the wings are 

 very long and pointed ; the feet are short and weak ; and the 

 hallux is either permanently turned sideways or forwards, or 

 can be made to assume this position at the will of the bird.' 

 The Swifts are very widely distributed in temperate and warm 

 regions. The " edible bird's-nests " of the Chinese are made 

 of the inspissated saliva of a Swift ( Collocalia). 



The Bee-eaters (Meropidce) live upon insects, chiefly upon 

 various species of bees and wasps ; but the Kingfishers live 

 upon small fish, which they capture by dashing into the water. 

 The common Kingfisher (Alcedo ispida] is a somewhat rare 

 native of Britain, and is perhaps the most beautiful of British 

 birds. Some exotic Kingfishers are of large size, and one of 

 the most remarkable of them is the Laughing Jackass (Dacelo 

 gigas) of Australia, so called from its extraordinary song, re- 

 sembling a prolonged hysterical laugh. A very beautiful species 

 is the belted Kingfisher ( Ceryle alcyon) of North America. 



The Bee-eaters are found chiefly in the warmer regions of 

 the Old World, and their place is taken in America by the 

 Motmots (Momotus). 



As regards their distribution in time, the Insessores are not 

 known in rocks older than the Tertiary. The Eocene Slates 

 of Claris have yielded the Passerine Protornis Glarisiensis ; 

 and in the Eocene deposits of the Paris basin occur remains 

 of the Passerine genera Laurillardia and Palczogithahis. The 



