3° 



Sclater on the Systema Avium. 



Subordo I. Aves CarinatvE. 



Series 

 Aigith ogn athina. 

 i. Passeres. 



2. Cypseli. 



3. Pici. 



Series 

 Desmognathina. 



4. Coccyges. 



5. Psittaci. 



6. Striges. 



7. Accipitres. 



8. Steganopodes. 



9. Herodiones. 

 10. Anseres. 



Series 

 Schizognathina. 



11. Columbse. 



12. Gallinae. 



13. Opisthocomi. 



14. Grues. 



15. Limicolas. 



16. Gaviae. 



17. Pygopodes. 



18. Impennes. 



Series 

 DroiiKTognathina. 

 19. Crypturi. 



Subordo II. A YES RATJT/E., 



20. Apteryges. 



21. Struthiones. 



I will now proceed to make a few remarks upon each of these 

 orders, and to state where I think there are improvements still 

 to be effected in the arrangement. It must, however, be always 

 recollected that, although a linear system is an absolute necessity 

 for practical use, it can never be a perfectly natural one. It will 

 always be found, in any linear arrangement, that certain groups 

 are nearly equally related to other groups at quite different parts 

 of the series, and that it is a question of no little difficulty with 

 which of these to place them ; but we must, nevertheless, do our 

 best to make the most natural linear arrangement that is possible 

 for practical use. 



1. Passeres. 



After eliminating the Scansores and Fissirostres of the Cuvier- 

 ian system, the remainder of the Insessores constitute a tolerably 

 homogenous group, which, it is now generally acknowledged, 

 form one of the main divisions of the Class of Birds. They are 

 the Passerinas of Nitzsch,* the Oscines of Sundevall's k Tenta- 

 men,' f the Coracomorphas of Huxley ; but I see no reason why 

 we should not retain for them the old Linnean name of Passeres. 



There are still several forms regarding which their collocation 

 in the Passeres thus understood is a matter of dispute. These 

 are mainly as follows : — 



1. Upupa. Sundevall places Upupa near the Larks, at the 

 commencement of his second series of Oscines (the "Oscines 



* ' Obs. de Avium arteria carotide communi.' Halse, 1829. 



t In Sundevall's former arrangement (Orn. Syst. 1836) they were denominated 

 Volucres, and divided into two main groups, Passeres and Oscines. 



