42 
ZOOLOGICAL GEOGRAPHY. 
[PART III. 
The Neotropical genera of Ranidoe, 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 Rio 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 ; 
Trichomyderus reaches 15,000 feet elevation in the Andes, — both 
belonging to the Siluridse ; Chirodon (2 sp.), belonging to the 
Characinidae, is peculiar to Chili ; and several other genera of the 
same family extend into this sub-region from Brazil. The family 
Haplochitonidae has a remarkable distribution ; one of its genera, 
Haplochiton (2 sp.), inhabiting Tierra del Euego and the Falkland 
Islands, while the other, Proiotroetes , is found only in South 
Australia and New Zealand. Still more remarkable is Galaxias 
(forming the family Galaxidae), the species of which are divided 
between Temperate South America, and Australia, Tas- 
mania, and New Zealand; and there is even one species 
{Galaxias attenuates) 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 Rio de la Plata 
— all belonging to the characteristic South American family of 
the Cyprinodontidfe. 
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. 
