witen on board h.m.. beagle a naturalit lwa much truck with certainfact in the ditribution of the organic being inhabiting outh america. and in thegeological relation of the preent to the pat inhabitant of that continent. theefact a will be een in the latter chapter of thi volume eemed to throw omelight on the origin of peciethat mytery of myterie a it h~a been called byone of our greatet philoopher. on my return home. it occurred to me. in i837that omething might perha be made out on thi quetion bypxatientlyaccumulating and reflecting on all ort of fact which could ibly have anybearing on it. after five year work 1 allowed myelf to peculate on the ubject.and drew up ome hort note; thee i enlarged in i844 into a ketch of theconcluion which then eemed to me probable: from that period to the preentday i have teadily purued the ame object. i hope that i may be excued forentering on thee peronal detail a i give them to how that i have not beenhaty in ing to a deciion.
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