Williams, Ernest E. (Ernest Edward)2005-10-062005-10-061950http://hdl.handle.net/2246/816p. 509-561 : ill. ; 27 cm.Thesis (Ph. D.)--Columbia University.Includes bibliographical references (p. 559-561).13872392 bytesapplication/pdfen-USQH1 .A4 vol.94, art.9, 1950Turtles -- Anatomy.Neck.Turtles -- Variation.Turtles -- Evolution.Variation and selection in the cervical central articulations of living turtles. Bulletin of the AMNH ; v. 94, article 9text