DIVIDED FAMILIES. 31 



in India and some of the islands of the Malay Archipelago, where 

 they constitute the genus Tragulus ; a solitary representative of the 

 same family, but belonging to a distinct genus (Hyomoschus), is a 

 native of West Africa. The anthropoid apes (Simiidse) are repre- 

 sented in Western (and probably also East Equatorial) Africa by 

 one or more species of gorilla and chimpanzee (Troglodytes), which 

 are almost exclusively confined to the forest region. The form most 

 nearly allied to these man-like apes, and belonging to the same 

 family, is the orang (Simla satyrus), which, as an inhabitant of the 

 islands of Sumatra and Borneo, is encountered after an interval of 

 not less than seventy degrees of longitude. Inhabiting the same 

 region, but with a northward extension to China, and westward to 

 Assam (south of the Brahmaputra River), we find the members of 

 the genus Hylobates, the gibbons. Probably the most striking 

 example of a divided family is furnished by the Camelidae, which 

 in the Old World are represented by the genus Camelus, with two 

 species — the dromedary and the Bactrian camel — whose habitat 

 extends from the Sahara through the desert regions of Western and 

 Central Asia to Lake Baikal ; and in the New World by the genus 

 Auchenia (the llama, alpaca, vicufia, and guanaco), with about four 

 species, all of them restricted to the mountainous and desert regions 

 of Western and Southern South America. We have here, therefore, 

 a family which is not only divided by a vast ocean and the greater 

 mass of two continents, but the members of which, in one hemi- 

 sphere, inhabit the region north of the Equator, and, in the other, 

 the region south of it. 



Instances of divided families among birds occur as in mammals, 

 although probably to a less marked extent, owing naturally to their 

 increased facilities for dispersion ; such division obtains more espe- 

 cially among the so-called " tropicopolitan " forms, or those whose 

 homes are properly the region of the tropics, or that immediately 

 adjoining it. The flamingoes (Phoenicopteridye), consisting of a 

 solitary genus and about eight species, are about equally distrib- 

 uted as to the number of species throughout the warmer regions 

 of America, Africa, and Asia, some of the forms extending their 

 range to a considerable distance within the bounds of the Tem- 

 perate Zone, as in Southern Europe and South America. The 

 trogons (Trogonidaj), comprising many of the most beautifully- 

 arrayed of birds, and with upwards of forty species, are more 



