VI CAPRIMULGI 415 



with Otus (i.e. Asio) and Buho ; the latter genus and Strio: occur 

 in the Lower Miocene of the same country, Strix also in the Malta 

 caverns and in the Mare aux Songes in Mauritius, Nyctea at 

 Torquay and in France, Bvho in Wyoming, Badiostes in Patagonia. 



The Sub-Order Caprimulgi consists of the Nightjar or Goat- 

 sucker group, with the Families Caprimvlgidae, Podargidae, and 

 Steatornitliidae, of which the latter contains only the remarkable 

 Guacharo. The Cajorvmulgidae may be divided into the Sub- 

 families (1) Caprimulginae and (2) Nyctihiiiiae. Authorities dis- 

 agree as to the exact relationship of these birds to their allies, here 

 classified as Coraciiformes ; but that all are allies is certain, while 

 both in appearance and habits Nightjars are decidedly Owl-like. 



Apart from the Steatornithidae, the skull is flattened, the eyes 

 are large, the beak is short and extremely broad, being hooked 

 and toothed in the Nyctibiinae and occasionally decurved in the 

 Caprimulginae and Podargidae ; the gape is enormously wide, and 

 is in many cases provided with stiff bristles, which in Aegotheles 

 have long lateral filaments. An appearance of great size is given 

 to the head by the loose plumage. The feet are fairly strong, with 

 the digits somewhat united basally ; the anteriorly scutellated 

 metatarsi vary from comparatively long and bare in Nyctidromus 

 and the Podargidae to very short and feathered in Nydihius. The 

 outer toe of the Caprimulginae has only four joints, and the mid- 

 toe has a pectinated claw, while in the Podargidae and some Capri- 

 mulginae the hallux is partially reversible. The pointed wing has 

 ten primaries, sometimes much elongated (p. 418), and eleven or 

 twelve secondaries ; the tail may be square, rounded, graduated, or 

 forked, and has ten rectrices, occasionally lengthened or even 

 racquet-tipped {loc. cit.). The furcula is U-shaped, the tongue 

 short ; the slit-like nostrils are basal and overhung by a membrane 

 and feathers in Podargus and Batrachostomus, whereas they are 

 open and near the tip of the bill in Aegotheles, but soft, tubular, 

 and often elongated in the Caprimulginae. The syrinx is bronchial, 

 sometimes tending to tracheo-bronchial ; the aftershaft is rudi- 

 mentary ; the adults have down only on the unfeathered tracts, 

 while the nestlings have a thick covering of it, which is generally 

 buff or grey, but white in Podargus and BatracJiostomus. 



The length varies from about twenty inches in Nyctibius and 

 Podargus to seven or eight in Caprimulgus parvidus and Phalae- 



