CARINAT^. 265 



other distinctive and exclusive peculiarity except tlie fact 

 that the feet o.re, 'provided, ivith four toes, of v:liich tim are 

 turned backwards and two forwards. Of the two toes which 

 are directed hachivards, one is the hallux or 2^'>^o]pct' hind-toe, 

 and the other is the outermost of the normal three anterior toes. 

 This arrano-ement of the toes enables the Scansores to climb 

 with unusual facility. Their powers of flight, on the other 

 hand, are generally only moderate and below the average. 



The most important families of the Scansores are the 

 Cuckoos {Cueulidm), the Woodpeckers and Wry -necks 

 {Pieidm), the Parrots {Psittaeidce), the Toucans {Rlianiphas- 

 tidce), the Trogons {Trogonidoi), the Barbets {Bucconidce), and 

 the Plantain-eaters {Musophagidoi). 



The range of the Scansores in time does not appear to be 

 extensive, the earKest known representative of the order being 

 from the lower Tertiary. The Eocene beds of Wyoming have 

 yielded the remains of a Woodpecker ( Uintornis), and Parrots, 

 Trogons, Cuckoos, and Woodpeckers are known to have lived 

 during the later Tertiary and Post-Tertiary periods. The 

 Miocene beds of Prance have yielded remains of Trogons 

 and Parrots, with forms related to the Plantain - eaters 

 {Necrornis), and others either referable to the Woodpeckers 

 (Picus) or allied to these (ITomalojjhics). 



Order V. Insessoees. — The fifth order of Carinate Birds 

 is that of the Insessorcs, or Perchers — often spoken of as the 

 Passeres, or " Passerine " Birds. They are defined by Owen 

 as follows : " Pegs slender, short, with three toes hefore and one 

 hehind, the two external toes tmited hy a very short memhrane." 



The Insessorcs form the largest order of existing birds, 

 comprising all the ordinary " song-birds," and including a 

 great nimiber of families. The earliest known remains of 

 Insessorial birds appear in the Eocene Tertiary. Thus in 

 the Lower Eocene Slates of Claris, we have the Protoniis 

 Glarisiensis, apparently allied to the Larks ; the Halcyornis 

 toliapiciis of the London Clay may be an old representative 

 of the Kingfishers ; the Upper Eocene Cryptornis seems to 

 be allied to the Hornbills ; and the Laurillardia and Palcm- 

 githalus of the same formation are peculiar Passerine types. 

 In the Miocene Tertiary we have Crows (Corvus), Wagtails 



