400 
ZOOLOGICAL G EOG RAPH Y. 
[PART 111. 
no actual land connection is required for birds which can cross 
considerable arras of the sea. 
Reptiles again seem to offer no more support to the view than 
do mammalia or birds. Among snakes there are no families in 
common that have not a very wide distribution. Among lizards 
the Gymnopthalmidse are the only family that favour the 
notion, since they are found in Australia and South America) 
but not in the Oriental region. Yet they occur in both the 
Palsearctic and Ethiopian regions, and their distribution is alto- 
gether too erratic to be of any value in a case of this kind ; 
and the same remarks apply to the tortoises of the family 
Clielydidee. 
The Amphibia, however, furnish us with some more decided 
facts. We have first the family of tree-frogs, Pelodryade, con- 
fined to the two regions ; Litoria , a genus of the family Hylidae 
peculiar to Australia, but with one species in Paraguay ; and in 
the family Discoglossidse, the Australian genus Chiroleptes has 
its nearest ally in the Chilian genus Calyptocephahis. 
Fresh-water fishes give yet clearer evidence. Three groups are 
exclusively found in these two regions ; Aphritis, a fresh-water 
genus of Trachinidae, has one species in Tasmania and two 
others in Patagonia ; the Haplochitonidse inhabit only Terra del 
Fuego, the Falkland Islands and South Australia; while the 
genus Galaxias (forming the family Galaxidse) is confined to 
South Temperate America, Australia, and New Zealand. We 
have also the genus Osieoglossum confined to the tropical 
rivers of Eastern South America, the Indo-Malay Islands and 
Australia. 
It is important here to notice that the heat-loving Reptilia 
afford hardly any indications of close affinity between the two 
regions, while the cold-enduring amphibia and fresh-water 
fish, offer them in abundance. Taking this fact in con- 
nection with the absence of all indications of close affinity 
among the mammalia and terrestrial birds, the conclusion seems 
inevitable that there has been no land-connection between the 
two regions within the period of existing species, genera, or 
families. Yet some interchange of amphibia and fresh- water 
