40 INTRODUCTION. 



concerning it will, of course, consult Mr. Mac Leay, and 

 the learned and luminous papers of Mr. Vigors before 

 mentioned. It may, however, be necessary to premise in 

 reference to the first diagram, that one of the families, 

 the Raptores, is still incomplete; this future inquiry may 

 probably fill up. It may also be mentioned here as a 

 singular coincidence, that Mrs. Barbauld, in a poem 

 written many years ago, expressly alludes to a quinary ar- 

 rangement of Birds in the following lines : 



41 Who the various nations can declare 

 That plough with busy whig the peopled air ? 

 These cleave the crumbling bark for insect foad^Insessores.) 

 Those dip the crooked beak in kindred blood ; (Raptores.) 

 Some haunt the rushy moor, the lonely woods ;(Grullatores.) 

 Some bathe their silver plumage in the floods ; (Natatores.) 

 Some fly to man, his household gods implore, (Rasores.) 

 And gather round his hospitable door, 

 Wait tiie known call, and find protection there, 

 From all the lesser tyrants of the air." 



By this arrangement, the first division of the whole family 

 of Birds, consisting of Insessores, Raptores, Rasores, 

 Grallatores, and Natatores, might be considered as 

 Classes, the division of each of which into five might constitute 

 Orders ; and the division of each of these again into five 

 might constitute the Genera. So that, if the Raptores should, 

 by subsequent discovery, be completed, the Classes, according 

 to this arrangement, will be five; the Orders twenty-five ; 

 and the Genera, one hundred and twenty-five. 



It appears, however, thatMR. Vigors thinks, by his observa- 

 tions in his Lectures at the Zoological Society, the quinary 

 system is applicable to the more minute subdivisions of nature, 

 and that the genera and species, &c. will be found to correspond 

 in similar and continuous subdivision. 



