SCANSORES INSESSORES RAPTORES. 395 



ORDER V. SCANSORES. The order of the Scansorial or 

 Climbing Birds is easily and very shortly denned, having no 

 other distinctive and exclusive peculiarity except the fact that 

 the feet are provided with four toes, of which two are turned 

 backwards and two forwards. Of the two toes which are 

 directed backwards, one, of course, is the hallux, or proper 

 hind-toe, and the other is the outermost of the normal three 

 anterior toes. This arrangement of the toes enables the Scan- 

 sores 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 

 (Cuculidtz), the Woodpeckers and Wry-necks (Picidce},t\iz Par- 

 rots (Psittacidce), the Toucans (Rhamphastid<z\ and the Tro- 

 gons (Trogonida). 



The Scansores are of small importance as fossils, but the 

 remains of Parrots, Trogons, Woodpeckers, and Cuckoos have 

 been detected in the later Tertiary and Post-tertiary deposits. 



ORDER VI. INSESSORES. The sixth order of Birds is that of 

 the Insessores, or Perchers often spoken of as the Passeres, 

 or "Passerine" Birds. They are defined by Owen as fol- 

 lows : 



"Legs slender, short, with three toes before and one behind, 

 the two external toes united by a very short membrane." 



The Insessores form the largest order of existing birds, com- 

 prising all the ordinary "song-birds," and including a great 

 number of families. The earliest known representatives of the 

 order in past time are the Protornis Glarisiensis of the Eocene 

 Schists of Claris, and the Haley ornis toliapicus of the London 

 Clay of Sheppey the former somewhat resembling the living 

 Larks, whilst the latter is supposed to be related to the King- 

 fishers. Besides these, a few unimportant forms have been 

 discovered in the later Tertiary and Post-tertiary deposits. 



ORDER VII. RAPTORES. All the members of this order are 

 characterised by the shape of the bill, which is "strong, curved, 

 sharp-edged, and sharp-pointed, often armed with a lateral 

 tooth " (Owen). The upper mandible is the longest, and is 

 strongly hooked at the tip. The body is very muscular ; the 

 legs are robust, short, with three toes in front and one behind, 

 all armed with long, curved, crooked claws or talons ; the 

 wings are commonly pointed, and of considerable size, and the 

 flight is usually rapid and powerful. 



The order Raptor es is divided into the two sections of the 

 Nocturnal and Diurnal Raptor es, comprising respectively the 

 forms which fly by night and those which fly by day. In the 



