HARTWEG, N., and OLIVER, J. A.

1940. A contribution to the herpetology of the Isthmus of Tehuantepec. IV. An annotated list of the amphibians and reptiles collected on the Pacific slope during the summer of 1936. Misc. Publ. Mus. Zool. Univ. Michigan, No. 47:1-31.

HUBBELL, T. H.

1954. Relationships and distribution of _Mycotrupes_. In The burrowing beetles of the genus _Mycotrupes_, Olson, A. L., Hubbell, T. H., and Howden, H. F. Misc. Publ. Mus. Zool.

Univ. Michigan, No. 84:1-59, pls. 1-8.

HUTCHINSON, G. E., PATRICK, R., and DEEVEY, E. S.

1956. Sediments of Lake Patzcuaro, Michoacan, Mexico. Bull.

Geol. Soc. Amer., vol. 67:1491-1504.

LANGEBARTEL, D. A., and SMITH, P. W.

1959. Noteworthy records of amphibians and reptiles from eastern Mexico. Herpetologica, vol. 15 (1):27-29.

MARTIN, P. S.

1958. Pleistocene ecology and biogeography of North America.

Zoogeography. Amer. a.s.soc. Advanc. Sci., Publ. No.

51:375-420.

MARTIN, P. S., and HARRELL, B. E.

1957. The Pleistocene history of temperate biotas in Mexico and eastern United States. Ecology, vol. 38:468-480.

OLIVER, J. A.

1948. The relationships and zoogeography of the genus _Thalerophis_ Oliver. Bull. Amer. Mus. Nat. Hist., vol.

92:157-280, pls. 16-19.

OLSON, E. C., and MCGREW, P. O.

1941. Mammalian fauna from the Pliocene of Honduras. Bull.

Geol. Soc. Amer., vol. 52:1219-1244.

RUTHVEN, A. G.

1912. The amphibians and reptiles collected by the University of Michigan--Walker Expedition in southern Vera Cruz, Mexico. Zool. Jahrbuch, vol. 32 (4):295-332, pls.

6-11.

SCHUCHERT, C.

1935. Historical geology of the Antillean-Caribbean region.

New York, xxvi + 811 pp.

SEARS, P. B., FOREMAN, F., and CLISBY, K. H.

1955. Palynology in southern North America. Bull. Geol. Soc.

Amer., vol. 66:471-530.

SHANNON, F. A., and WERLER, J.

1955. Notes on amphibians of the Los Tuxtlas Range of Veracruz, Mexico. Trans. Kansas Acad. Sci., vol. 58 (3):360-386.

SHREVE, B.

1957. Reptiles and amphibians from the Selva Lacandona. _In_ Biological Investigations in the Selva Lacandona, Chiapas, Mexico. Paynter, R. A. (editor). Bull. Mus. Comp. Zool., vol. 116 (4):193-298.

SMITH, H. M.

1947. Notes on Mexican amphibians and reptiles. Jour.

Washington Acad. Sci., vol. 37:408-412.

SMITH, H. M., and LAUFE, L. E.

1946. A summary of Mexican Lizards of the genus _Ameiva_.

Univ. Kansas Sci. Bull., vol. 31 (2):7-73.

SMITH, H. M., and TAYLOR, E. H.

1950. An annotated checklist and key to the reptiles of Mexico exclusive of the snakes. Bull. U. S. Natl. Mus., No.

199, v + 253 pp.

STIRTON, R. A.

1954. Late Miocene mammals from Oaxaca, Mexico. Amer. Jour.

Sci., No. 252:634-638.

STUART, L. C.

1935. A contribution to a knowledge of the herpetology of a portion of the savanna region of central Peten, Guatemala.

Misc. Publ. Mus. Zool. Univ. Michigan, No. 29:1-56, pls.

1-4.

1941. Studies of Neotropical Colubridae VIII. A revision of the genus _Dryadophis_ Stuart, 1939. Misc. Publ. Mus. Zool.

Univ. Michigan, No. 49:1-106, pls. 1-4.

1951. The herpetofauna of the Guatemalan Plateau, with special reference to its distribution on the southwestern highlands. Contrib. Lab. Vertebrate Biol., Univ. Michigan, No. 49:1-71, pls. 1-7.

1954. A description of a subhumid corridor across northern Central America, with comments on its herpetofaunal indicators. Contrib. Lab. Vertebrate Biol., Univ. Michigan, No. 65:1-26, pls. 1-6.

1958. A study of the herpetofauna of the Uaxactun-Tikal area of northern El Peten, Guatemala. Contrib. Lab. Vertebrate Biol., Univ. Michigan, No. 75:1-30.

TAYLOR, E. H.

1940. New species of Mexican Anura. Univ. Kansas Sci. Bull., vol. 26 (11):385-405.