INSESSORES. Ill 



the more typical groups of these. The " first is, feet of that 

 construction most adapted for perching or grasping, the hind 

 toe always present, and articulated upon the same plane with 

 the fore toes ; second, the absence of the strongly defined 

 tooth which gives to the Rapacious birds the exclusive power 

 of tearing or dividing their food previous to swallowing it ; 

 and, thirdly, by the presence in the typical groups of a small 

 notch on one or both mandibles, enabling the bird to hold, 

 but not divide its food, which is swallowed in a whole state." 

 In addition to these distinctions of external form, it may be 

 observed, that the Insessorial birds possess a greater volume 

 of brain as compared with the other orders, and an intelli- 

 gence proportionally superior ; indicating in this respect also 

 the typical superiority they hold in this class of the animal 

 kingdom. The five primary tribes or divisions of the order 

 have long been recognised by CUVIER, ILLIGER, and other 

 eminent naturalists, and are now universally adopted. These 

 are the Fissirostres, Dentirostres, Conirostres, Scansores, 

 and Tenuirostres.* Of these the Dentirostres and Coni- 

 rostres are the typical tribes, being distinguished by their 

 more perfect construction, and the possession of qualities of 

 which the others are destitute^ or in which they exist only in 

 a limited degree. Each tribe is again divisible into circular 

 groups of subordinate value, distinguished as families, sub- 

 families, and genera, which last may be considered as the 

 lowest on the scale. 



TRIBE I. FISSIROSTRES, Cuv. 



The Fissirostres are distinguished from the more typical 

 tribes by the weak conformation of their legs and feet, by 

 the width of their rictus or gape (the bill being always broad 



" I have here to observe, that throughout this work, the arrangement 

 adopted by Mr VIGORS, of placing the more perfect or typical forms in 

 the centre, and the aberrant on each side, has been pursued. 



