CH. i] GENERA AND SPECIES OF LIMITED RANGE. 11 



catalogue of them. A few of the more remarkable ex- 

 amples may however be referred to. The most striking of 

 these are certain fishes which are limited to a single lake ; 

 thus the Lough Killin Charr is confined to the lake of 

 that name. A small moth, Ornix devoniella, was once only 

 found in Devonshire. The monkeys of the genus Brachy- 

 urus, comprising three species, are limited each to a 

 moderately small forest tract in South America. The 

 majority of examples of species with a limited range 

 are of course to be found upon oceanic islands. Not 

 only are there species with a very small range in space 

 but also genera. Here again the most numerous examples 

 are to be found on oceanic islands such as the now extinct 

 Starling, Fregilupus, of Reunion. But there are other 

 cases of genera which have facilities for a wider range, 

 but which for one reason or another (to be considered 

 later) have been unable to extend that range. The genus 

 Opisthocomus (containing by the way only a single species, 

 being the type of a distinct family) is limited to a portion 

 of British Guiana ; the Gorilla to the forest tract of the 

 west coast of Africa ; here again there is but one species. 

 Among families there are also a few with an exceedingly 

 restricted distribution. The Rhinochetidse, containing only 

 one genus and species, R. j-uhatus, the Kagu, is only found 

 in the island of New Caledonia; the Trumpeters or 

 Psophiidse are confined to certain districts of the Amazons, 

 and the four or five species of the genus might be quoted 

 as a case of very limited range in species. In Madagascar 

 the family Chiromyidae is represented by but one species. 

 Cases of limited range among groups that maybe regarded 



