SPREADING OF BIRDS. 71 



Latitude. The Bittern (A.stellaris) approaches near- 

 est to the Polar Circle. The other species are met 

 with more to the South. Sixteen species of this 

 Genus are found in Germany. 



13. Rails (Rallus) are found, in some species, in 

 both Hemispheres, but keep at some distance from 

 the snow-line. The Landrail (JR. crex) inhabits the 

 Temperate Zone as far as Norway, and is seen even 

 in Russia and Siberia. The Waterbill-Cock (R. aqua- 

 ileus) does not, in like manner, leave the Temperate 

 Zone. On the Southern Hemisphere, a species is 

 met with (R. obscurus) in the Sandwich Islands, 

 and the jR. troglodytes in New-Zealand. Several 

 species live in Cayenne, Jamaica, and similar regions. 



14. Moor-Hens (Fulica) are closely related to 

 that of the Rails ; but appear, like that of the Pra- 

 tincoles (Glareola), to be found only in the North- 

 ern Hemisphere. The common Moor-Hen (F. atra) 

 inhabits the whole of the Old World, as far as Nor- 

 way, Jamaica, Carolina, and Greenland. 



15. The Plover (Charadrius) spreads over the zones 

 of both Hemispheres, as far as the snow-line. The 

 common Plover (Ch. pluvialis) is met with in Lap- 

 land, Iceland, Hudson's Bay, and in Labrador ; the 

 Grey Plover (Ch. apricarius), in Iceland, Greenland, 

 and Hudson's Bay. Two species, Ch. novce Seelan- 



