The primary factors of organic evolution - Cope, E. D. (Edward Drinker), 1840 -1897 (The Open Court Publishing Company, 1896)

The primitive streak and notochordal canal in Chelonia - Davenport, Gertrude Anna Crotty, 1866 - (Ginn, 1896)

The principles of biology, by J. I. Hamaker - Hamaker, John Irvin, 1869 - (P. Blakiston, 1913)

The principles of biology - Hamaker, J. I. (John Irvin), 1869 - (P. Blakiston's Sons & Co, 1913)

Principles of economic zoölogy - Daugherty, L. S. (Lewis Sylvester) 1857 -1919 (W. B. Saunders Company, 1917)

Principles of economic zoo̤logy - Daugherty, L. S. (Lewis Sylvester) 1857 -1919 (W.B. Saunders, 1915)

Principles of economic zoölogy - Daugherty, L. S. (Lewis Sylvester) 1857 -1919 (W. B. Saunders company, 1912)

Principles of economic zoölogy - Daugherty, L. S. (Lewis Sylvester) 1857 -1919 (W. B. Saunders, 1917)

Principles of economic zoölogy - Daugherty, L. S. (Lewis Sylvester) 1857 -1919 (W.B. Saunders, 1912)

Principles of stratigraphy - Grabau, Amadeus W. (Amadeus William), 1870 -1946 (A.G. Seiler and company, 1913)

Principles of zoölogy : a guide for beginners - Schiedt, Richard Francis Conrad, 1859 -1951 (Examiner Printing House, 1892)

Problems in biology - Hunter, George W. (George William), 1873 -1948 (American book company, 1935)

Proceedings - Dorset Natural History; Archaeological Society.

Proceedings and Transactions of the Croydon Microscopical & Natural History Club - Croydon Microscopical; Natural History Club. (1871)

Proceedings and transactions of the Natural History Society of Glasgow - Natural History Society of Glasgow. (The Society, 1889)

Proceedings and transactions of the Royal Society of Canada. Délibérations et mémoires de la Société royale du Canada - Royal Society of Canada. (Société royale du Canada, 1904)

Proceedings and transactions of the Royal Society of Canada. Délibérations et mémoires de la Société royale du Canada - Royal Society of Canada. (Société royale du Canada, 1907)

Proceedings - Dorset Natural History and Archaeological Society - Dorset Natural History; Archaeological Society. (1877)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1861)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1862)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1864)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1865)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1867)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1866)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1868)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1871)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1874)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1875)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1876)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1882)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1883)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1892)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1894)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1896)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1902)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1903)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1908)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1913)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1915)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1841)

Proceedings of the American Philosophical Society held at Philadelphia for promoting useful knowledge - American Philosophical Society. (American Philosophical Society, 1869)

Proceedings of the American Philosophical Society held at Philadelphia for promoting useful knowledge - American Philosophical Society. (American Philosophical Society, 1871)

Proceedings of the American Philosophical Society held at Philadelphia for promoting useful knowledge - American Philosophical Society. (American Philosophical Society, 1877)

Proceedings of the American Philosophical Society held at Philadelphia for promoting useful knowledge - American Philosophical Society. (American Philosophical Society, 1878)

Proceedings of the American Philosophical Society held at Philadelphia for promoting useful knowledge - American Philosophical Society. (American Philosophical Society, 1879)

Proceedings of the American Philosophical Society held at Philadelphia for promoting useful knowledge - American Philosophical Society. (American Philosophical Society, 1883)

Proceedings of the American Philosophical Society held at Philadelphia for promoting useful knowledge - American Philosophical Society. (American Philosophical Society, 1885)