3 o 4 BIRDS. 



7. Stegaxopodes — Pelicans, Cormorants, and Gannets. 



8. Herodioxes — Herons and Storks. 



9. Odoxtoglossi — Flamingos. 



10. Axseres — Ducks, Geese, and .Swans. 



1 1. Palame i )E.e — Screamers. 



12. Coeumb.e — Pigeons, Dodo, and Sand-Grousa 



13. GaujNjE — Fowls and Game-Birds. 



14. Fulicari.e — Rails and Coots. 



15. Alectorides — Cranes and Bustards. 



16. L1.MIC0L.E — Plovers, Curlews, Snipe etc. 



17. Gayl.e — Gulls and Terns. 



LS. Tubinares — Petrels an' 1 Albatrosses. 



19. Pygopodes — Divers, Auks, and Grebes. 



20. Impexxes — Penguins. 



21. ODONTOBNITHES — Toothed Bird- (extinct). 



22. Crypturi — Tinamus. 



23. Katit.e — Ostriches, Emeus, Cassowaris, etc. 



24. Saurur.e — Long-Tailed Birds (extinct). 



Of these groups the first twenty-two, which are reckoned as orders, are 

 brigaded together to form the subclass of Carinate Birds (Carinatse), the great 

 majority of which possess the power of flight, and have a strong keel (carina) to 

 the breast-hone. The twenty-third group, or Ratitse, constitutes, on the other 

 hand, a second subclass, characterised by the absence of a keel to the breast-bone, 

 and the loss of the power of flight: while the extinct long-tailed birds (group 

 24) form a third main division differing from all the others by the retention 

 of the long reptilian tail. 



The number of existing species of birds being in all probability considerably 

 over ten thousand, it will lie obvious that in the space at our command the various 

 groups must be treated much more briefly than were the Mammals; ami in many 

 instances we shall be able to allude only to the families, without referring to the 

 genera, and in some cases not even the whole of the former are mentioned. 



It will be noticed that in the course of this Introduction practically nothing- 

 has been said as to the anatomy of the soft parts of birds; for this wc must refer 

 the reader to other works. 



