. Island life; or, the phenomena and causes of insular faunas and floras, including a revision and attempted solution of the problem of geological climates. able discontinuous distribution, asshown in the accompanying map, one portion of its area com-prising Central and South Europe and Asia Minor, the otheran undefined tract in Northern China, the two portions beingthus situated in about the same latitude and having a verysimilar climate, but with a distance of about 4,000 miles be-tween them. If, however, these two forms are reckoned assub-species only, then the area of the species becomes c
. Island life; or, the phenomena and causes of insular faunas and floras, including a revision and attempted solution of the problem of geological climates. able discontinuous distribution, asshown in the accompanying map, one portion of its area com-prising Central and South Europe and Asia Minor, the otheran undefined tract in Northern China, the two portions beingthus situated in about the same latitude and having a verysimilar climate, but with a distance of about 4,000 miles be-tween them. If, however, these two forms are reckoned assub-species only, then the area of the species becomes con-tinuous, while only one of its varieties or sub-species has adiscontinuous area. It is a curious fact that P. pxf^lustris andP horealis are found together in Southern Scandinavia and insome parts of Central Europe, and are said to differ somewhatin their note and their habits, as well as in colouration. Discontinuity of Emheriza schoeniclus.—The other case is thatof our reed bunting {Erabeinza schceniclus), which ranges overalmost all Europe and Western Asia as far as the Yenesai valleyand North-west India. It is then replaced by another smaller. AUBURI:!, ALA. niAP. IV.] EVOLUTION THE KEY TO DISTRIBUTION. ^5 species, E. passerma, which ranges eastwards to the Lena river,and in wiuter as far south as Amoy in China; but in Japanthe original species appears again, receiving a new name (), but Mr. Seebohm assures us that it is quiteindistinguishable from the European bird.^ Although thedistance between these two portions of the species is not sogreat as in the last example, being about 2,000 miles, in otherrespects the case is a most satisfactory one, because the formswhich occuj^y the intervening space are recognised by himself as undoubted species. The European and Japanese Jays.—Another case somewhatresembling that of the marsh tit is afforded by the Europeanand Japanese jays {Garrulns glandarins and G. jap)onicus). Ourcommon jay inhabits the whole
Size: 1200px × 2082px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorwallacealfredrussel18, bookcentury1800, bookdecade1880
