he several areas, and the isolation of many of the
species; while the next most striking feature is the manner in which the
Asiatic species almost surround a vast area in which no jays are found. The
only species with large areas, are the European _G. glandarius_ and the
Asiatic _G. Brandti_. The former has three species overlapping it--in
Algeria, in South-eastern and North-eastern Europe respectively. The Syrian
jay (No. 4), is not known to occur anywhere with the black-headed jay (No.
3), and perhaps the two areas do not meet. The Persian jay (No. 5), is
quite isolated. The Himalayan and Chinese jays (Nos. 7, 8, and 9) form a
group which are isolated from the rest of the genus; while the Japanese jay
(No. 11), is also completely isolated as regards the European jays to which
it is nearly allied. These peculiarities of distribution are no doubt in
part dependent on the habits of the jays, which live only in well-wooded
districts, among deciduous trees, and are essentially non-migratory in
their habits, though sometimes moving southwards in winter. This will
explain their absence from the vast desert area of Central Asia, but it
will not account for the gap between the North and South Chinese species,
nor for the absence of jays from the wooded hills of Turkestan, where Mr.
N. A. Severtzoff collected assiduously, obtaining 384 species of birds but
no jay. These peculiarities, and the fact that jays are never very abundant
anywhere, seem to indicate that the genus is now a decaying one, and that
it has at no very distant epoch occupied a larger and more continuous area,
such as that of the genus Parus at the present day.

_Discontinuous generic Areas._--It is not very easy to find good examples
of genera whose species occupy two or more quite disconnected areas, for
though such cases may not be rare, we are seldom in a position to mark out
the limits of the several species with sufficient accuracy. The best and
most remarkable case among European birds is {24} that of the blue magpies,
forming the genus Cyanopica. One species (_C. cooki_) is confined (as
already stated) to the wooded and mountainous districts of Spain and
Portugal, while the only other species of the genus (_C. cyanus_) is found
far away in North-eastern Asia and Japan, so that the two species are
separated by about 5,000 miles of continuous land. Another case is that of
the curious little water-moles forming the genus Mygale, one species _M.
muscovitica_