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42 ZOOLOGICAL GEOGRAPHY. [pabtiii.
The Neotropical genera of Eanidse, five of which extend to
Chili and Patagonia, belong to a division which is Australian
and Neotropical, and which has species in the Oriental and
Ethiopian regions.
Fresh-water Fishes.—These present some peculiar forms, and
some very interesting phenomena of distribution. The genus
Percilia has been found only in the Eio de Maypu in Chili ; and
Percichthys, also belonging to the perch family, has five species
confined to the fresh waters of South Temperate America, and
one far away in Java. Nematogenys (1 sp.) is peculiar to Chili
Trichomycterusre,diQ\\QB 15,000 feet elevation in the Andes,—both
belonging to the Siluridse ; Ghirodon (2 sp.), belonging to the
Characinidse, is peculiar to Chili ; and several other genera of the
same family extend into this sub-region from Brazil. The family
Haplochitonidse has a remarkable distribution ; one of its genera,
Haplochiton (2 sp.), inhabiting Tierra del Fuego and the Falkland
Islands, while the other, Frototroctes, is found only in South
Australia and New Zealand. Still more remarkable is Galaxias
(forming the family Galaxidse), the species of which are divided
between Temperate South America, and Australia, Tas-
mania, and New Zealand; and there is even one species
(Galaxias attenuatus) which is found in the Chatham Islands,
New Zealand, and Tasmania, as well as in the Falkland
Islands and Patagonia. Fitzroya (1 sp.) is found only at
Montevideo ; Orestias (6 sp.) is peculiar to Lake Titicaca in the
high Andes of Bolivia; Jenynsid (1 sp.) in the Eio de la Plata
—all belonging to the characteristic South American family of
the Cyprinodontidse.
Insects.—It is in insects more than in any other class of animals,
that we find clear indications of a not very remote migration of
northern forms, along the great mountain range to South Tem-
perate America, where they have established themselves as a
prominent feature in the entomology of the country. The
several orders and families, however, differ greatly in this
respect ; and there are some groups which are only represented
by modifications of tropical forms, as we have seen to be almost
entirely the case in birds and reptiles.