SCLATER ON THE GENERAL DISTRIBUTION OF AYES. 



133 



ture's unvarying laws of distribution. It is, however, amongst 

 the Passeres that we find endemism most normal ; the Accipitres, 

 Anseres, and, more than all, the Grallce are ever disposed to be 

 sporadic, and indeed some species belonging to the latter order may 

 be denominated truly cosmopolitan. 



Taking then the birds of the order Passeres (which I consider 

 ought properly to include the Scansores or Zygodactyly as the chief 

 materials from which to derive our deductions, let us suppose a 

 species of this group, but of doubtful form and obscure plumage, 

 to be placed before the Ornithologist, from whom its name is re- 

 quired. The first thing he looks to is, whether it is from the Old 

 "World or the New ; and this is a point which, as a general ride, a 

 mere glance at the external appearance of the object is sufficient to 

 settle. The most obvious geographical division of the birds of this 

 order certainly corresponds with the usually adopted primary divi- 

 sion of the earth's surface. In fact, taking Ornithology as our 

 guide, we may at once pronounce that the Faunae of the Old and 

 New worlds may, to all appearance, have been the subjects of dif- 

 ferent acts of creation. There are very many natural families which 

 are quite peculiar to one or the other of these great divisions of 

 the earth's surface, more subfamilies, few genera, really common 

 to the two, and very few, if any, species*. 



The appended Table will show some of the most noticeable of 

 the natural families of birds which are confined to the Old and 

 New worlds respectively. 



Familiae Neogeanae, 

 sive Novi Orbis. 



Familiae Palaeogeanae, 

 sive Orbis Veteris. 



Todidae. Tyrannidae. Coraciidse. Promeropidae. 



Momotidae. Cotingidae. , Eurylaemidae. Muscicapidae. 



Bucconida?. Rhamphastidae. '■ Meropidae. Musophagidae. 



Galbulidae. Opisthocomidae. Upupidae. Coliidae. 



Trochilidae. Cracidae. I Bucerotidae. Megapodidaj. 



Icteridae. Tinamidae. Stmnidae. Pteroclidae. 



Caerebidae. Meleagrinae. [ Paradiseidas. Phasianidae. 



Formicariidae. Odontophorinae. j Meliphagidae. Perdicinae. 

 Dendrocolaptidae. 



With regard to the genera of Passeres, common to the two 

 worlds, when we have excepted the truly cosmopolitan forms 

 Turdus, Hirundo, Picus, &c, the number will be found very 

 small ; and it will be observed that these are invariably genera 



* There are now acknowledged only 8 species of the order Passeres, in 



