SYNOPSIS. The American Society of Zoologists as we know it today descended from two immediate progenitors, the American Morphological Society and the Western Branch of the American Society of Naturalists. The latter group was known during 1901 and 1902 as the Society of American Zoologists. The two organizations formed the American Society of Zoologists at the American Society of Naturalists' 1902 meeting in Washington, D.C. The American Society of Zoologists first formed with two Branches, the Eastern and the Central. These two Branches merged into a single Society after the 1913 meeting in Philadelphia.