Proceedings of the Academy of Natural Sciences of Philadelphia. Academy of Natural Sciences of Philadelphia. text [Philadelphia : Academy of Natural Sciences of Philadelphia], 1841- eng v. : 23-25 cm. "Publications of the Academy of Natural Sciences of Philadelphia": v. 53, 1901, p. 788-794. Vols. for 1857-1900 are unnumbered. In lists on covers the vols. are arranged in series: 1st ser. 1841/43-1856 (8 v.); 2d ser. 1857-70 (14 v.); 3d ser. 1871-<1922 (52 v.)> Index to years 1841-1910 is included in "An index to the scientific contents of the Journal and Proceedings of the Academy of Natural Sciences of Philadelphia ... 1913." Chemical abstracts Academy of Natural Sciences of Philadelphia -- Periodicals Natural history -- Periodicals. Science -- Periodicals. Also issued online via the World Wide Web. Proceedings of the Academy of Natural Sciences of Philadelphia (Online)