r three species in South America, and one very distinct species in
Malacca and Borneo, separated by nearly half the circumference of the
globe. Another example among quadrupeds is a peculiar genus of moles named
Urotrichus, of which one species inhabits Japan and the other British
Columbia. The cuckoo-like honey-guides, forming the genus Indicator, are
tolerably abundant in tropical Africa, but there are two outlying species,
one in the Eastern Himalaya mountains, the other in Borneo, both very rare,
and recently an allied species has been found in the Malay peninsula. The
beautiful blue and green thrush-tits forming the genus Cochoa, have two
species in the Eastern Himalayas and Eastern China, while the third is
confined to Java; the curious genus Eupetes, supposed to be allied to the
dippers, has one species in Sumatra and Malacca, while four other species
are found two thousand miles distant in New Guinea; lastly, the lovely
ground-thrushes of the genus Pitta, range from Hindostan to Australia,
while a single species, far removed from all its near allies, inhabits West
Africa.

_Peculiarities of Generic, and Family Distribution._--The examples now
given sufficiently illustrate the mode in which the several species of a
genus are distributed. We have next to consider genera as the component
parts of families, and families of orders, from the same point of view.
{26}

All the phenomena presented by the species of a genus are reproduced by the
genera of a family, and often in a more marked degree. Owing, however, to
the extreme restriction of genera by modern naturalists, there are not many
among the higher animals that have a world-wide distribution. Among the
mammalia there is no such thing as a truly cosmopolitan genus. This is
owing to the absence of all the higher orders except the mice from
Australia, while the genus Mus, which occurs there, is represented by a
distinct group, Hesperomys, in America. If, however, we consider the
Australian dingo as a native animal we might class the genus Canis as
cosmopolite, but the wild dogs of South America are now formed into
separate genera by some naturalists. Many genera, however, range over three
or more continents, as Felis (the cat genus) absent only from Australia;
Ursus (the bear genus) absent from Australia and tropical Africa; Cervus
(the deer genus) with nearly the same range; and Sciurus (the squirrel
genus) found in all the continents but Australia. Among birds T