GEOGRAPHY OX THE MALAY ARCHIPELAGO. 
183 
tinent, it ia still an impassable barrier against the passage of any 
considerable number and variety of land animals ; and that in all 
cases in which such islands possess a tolerably rich and varied 
fauna of species mostly identical, or closely allied with those of 
the adjacent country, we are forced to the conclusion that a geo- 
logically recent disruption has taken place. Great Britain, Ire- 
land, Sicily, Sumatra, Java and Borneo, the Aru Islands, the 
Canaries and Madeira, are cases to which the reasoning is fully 
applicable. 
In his introductory Essay on the Flora of New Zealand, Dr. 
Hooker has most convincingly applied this principle to show the 
former connexion of New Zealand and other southern islands with 
the southern extremity of America; and I will take this opportunity 
of calling the attention of zoologists to the very satisfactory man- 
ner in which this view clears away many difficulties in the distri- 
bution of animals. The most obvious of these is the occurrence 
of Marsupials in America only, beyond the Australian region. 
They evidently entered by the same route as the plants of New 
Zealand and Tasmania which occur in South temperate America, 
but having greater powers of dispersion, a greater plasticity of 
organization, have extended themselves over the whole continent 
though with so few modifications of form and structure as to point 
to a unity of origin at a comparatively recent period. It is among 
insects, however, that the resemblances approach in number and 
degree to those exhibited by plants. Among Butterflies the beau- 
tiful Heliconidce are strictly confined to South America, with the 
exception of a single genus {Kamadryas) found in the Australian 
region from New Zealand to New Guinea. Iii Coleoptera many 
families and genera are characteristic of the two countries ; such 
are Pseudomorphidce among the Geodephaga, Lamprimidw and 
Syndesid<e among the Lucani, Anoplognathidce among the Lamel- 
licornes, Stigmoderides among the Buprestes, Natalis among the 
Cleridie, besides a great number of representative genera. This 
peculiar distribution has hitherto only excited astonishment, and 
has confounded all ideas of unity in the distribution of organic 
beings ; but we now see that they are in exact accordance with the 
phenomena presented by the flora of the same regions, as developed 
in the greatest detail by the researches of Dr. Hooker. 
It is somewhat singular, however, that not one identical species 
of insect should yet have been discovered, while no less than 89 
Bpecies of flowering plants are found both in New Zealand and 
South America. The relations of the animals and of the plants 
