FLIGHTLESS BIRDS. 21 
have survived (for such time as they did survive) by virtue 
of the fact that they had no enemies to cope with. Almost 
without exception birds of this class have been met with 
on islands where the surrounding conditions have been 
particularly favourable to their existence, and where there 
has been an absence of enemies in the shape of predatory 
mammals to. cause them discomfort. Such birds have 
been more numerous than might have been anticipated, 
and some few still survive. The Mauritian group of islands 
in the Indian Ocean, to the east of Madagascar, have 
furnished some of the best-known examples. Mauritius 
itself supplied the celebrated Dodo, Didus ineptus; the 
sister island, Rodriguez, gave birth to another Didine bird 
—the Solitaire, Pezophaps solitarius ; whilst it is known 
that another island of this group, Bourbon, was at one 
time inhabited by a flightless bird, allied to the above two, 
but no trace of this is now known to exist. Other flight- 
less birds, however, besides the Didine group, at one time 
inhabited these islands, such as the flightless rail, dphan- 
-apteryz, from Mauritius; and there were brevipennate 
birds, such as the large Heron, Ardea megacephala, from 
Rodriguez. But the New Zealand region has probably 
been more prolific of birds of this kind than any other 
portion of the world. ‘hus, amongst birds still existing, 
we have the different species of Woodhen—Ocydromus, 
the large ralline bird Notornis, the Owl Parrot Strigops, 
from New Zealand proper; and the small Duck, Neso- 
netta aucklandica, from the Auckland Islands. Whilst 
amongst extinct forms from the same zoological region 
may be mentioned the giant Woodhen, Aptornis, and a 
huge anserine bird, Cnemiornis. The Chatham Islands, 
again, have furnished other instances of flightless rails, 
‘such as Palgolimnas, Nesolimnas, and Diaphorapteryz, 
though the first named of these may possibly still have 
