INSESSORES. 101 



ing ; the hallux or hind toe being always present, and articulated on the same plane 

 with the fore toes. 



Secondly, by the absence of that strongly-defined tooth, which gives to the 

 rapacious birds the exclusive power of tearing or dividing their food, previous to 

 swallowing- it. 



Thirdly, by the presence, in the typical groups, of a small notch in one or 

 both mandibles, enabling the bird to hold, but not divide, its food, which is 

 swallowed almost universally in an entire state. 



The two first distinctions are much more positive and universal than the last ; 

 but the whole will sufficiently detach the Perchers from all other birds. 



The primary divisions of this order are so obvious, that the most inexperienced 

 student cannot fail to perceive them. The Dentirostres, Conirostres, Scan- 

 sores, Tenuirostres, and Fissirostres, are so many prominent groups, which 

 have been long recognised in the celebrated Prodromus of Illiger, the Regne 

 Animal of Cuvier, and sufficiently so in other works ; they have been accordingly 

 cited, with justice, to illustrate the circular nature of the Insessores. So far 

 as regards the admission of these groups, nothing more need be said, since 

 they have been universally adopted. This unanimity, however, among orni- 

 thologists merely extends to the typical forms ; all agree, for instance, in classing 

 the Woodpeckers and Parrots as climbing birds. But because the scansorial 

 structure is exhibited under a different form in the Grimpereaux of M. Cuvier, we 

 find these birds occupying a station in the Regne Animal with the Tenuirostres. 

 Even this latter tribe, by some writers, is made to embrace every bird suspected 

 of having a filamentous tongue, however strongly it may be allied, in all other 

 parts of its organization, with groups far differently situated. When, therefore, 

 it is said that the five sub-orders or tribes above named have been universally 

 admitted, it must be at the same time remembered that no two writers have yet 

 agreed on their definite nature. Hence it becomes advisable, before we proceed 

 further, to attempt their true definition. 



We have already stated an opinion, that the Insessorial order first resolves 

 itself into three circular groups ; by which disposition the Scansores, the Tenui- 

 rostres, and the Fissirostres, are united into one ; and that the two others, namely, 

 the Conirostres and the Dentirostres, constitute the typical and the subtypical 

 circles. Their prominent distinctions may be thus stated : — 



