242 ZOOLOGICAL GxVRDENS. 



office is simply to entrap the insects that float along 

 the air, it is excessively broad and short. An inter- 

 mediate structure occurs in a third series, the Denti- 

 rostres, in which the bill is somewhat elongated, and 

 furnished with a notch on either side of the upper 

 mandible near the point, by which provision those 

 birds are enabled to capture not only the insects which 

 form their more usual prey, but also not unfrequently 

 the smaller birds. The bill becomes still more elon- 

 gated, but with increased strength and without denti- 

 culation, in the Conirostres, whose food is generally of 

 a mixed nature, partly animal and partly vegetable. 

 Among the birds of this subdivision it attains its maxi- 

 mum of developement ; but still retains a high degree 

 of power in the remaining section of the order, the 

 Scansores, which, like the last, feed partly upon seeds 

 and partly upon insects, and even occasionally upon 

 eggs and birds, and in which various modifications of 

 bill are connected together by a peculiar arrangement 

 of the toes. Thus the Perchers exhibit almost every 

 possible gradation between the bills of the Humming- 

 birds and those of the Hornbills, the smallest and 

 slenderest on the one hand, and on the other the 

 largest and most apparently disproportioned, that are 

 met with among birds. 



But with all these diversities in the form of their 

 bills and in the nature of their food, the Insessorial 

 birds possess one character in common, of paramount 

 importance, inasmuch as it is that by which their mode 

 of life and their station among the works of the creation 

 are chiefly determined. The character to which we 

 allude is that which gives name to the order, the 

 faculty, par excellence, of perching upon trees. Other 

 birds, it is true, possess the same power to a certain 

 extent ; but in none of them is it carried to so high a 



