For financial assistance with field work I am grateful to Rollin H. Baker, and those individuals who administer the Michigan State University Development Fund and the Bache Fund of the National Academy of Sciences (Grant No. 463). I am grateful also to J. Keever Greer, Donald F. Switzenberg, and Rudolph A. Scheibner for aid in the field, to Edward H. Taylor, James R. Dixon, and William E. Duellman for profitable discussions, and to Thomas Sweringen for figure 1. The specific name alludes to the habitat (Latin, _saxatilis_ = found among rocks). LITERATURE CITED DIXON, J. R. 1957. Geographic variation and distribution of the genus Tomodactylus in Mexico. Texas Journ. Sci., 9(4):379-409, 5 figs., 1 map, December. DUELLMAN, W. E., and DIXON, J. R. 1959. A new frog of the genus _Tomodactylus_ from Michoacan, Mexico. Texas Journ. Sci., 11(1):78-82, 1 fig., 1 table, March. FIRSCHEIN, I. L. 1954. Definition of some little-understood members of the leptodactylid genus _Syrrhophus_, with a description of a new species. Copeia, 1954, 1:48-58, February 19. LANGEBARTEL, D. A., and SHANNON, F. A. 1956. A new frog (_Syrrhophus_) from the Sinaloan lowlands of Mexico. Herpetologica, 12(3):163-165, 2 figs., September 1. SMITH, H. M., and TAYLOR, E. H. 1948. An annotated checklist and key to the Amphibia of Mexico. Bull. U. S. Nat. Mus., No. 194, pp. iv + 118. TAYLOR, E. H. 1940. Herpetological miscellany. Univ. Kansas Sci. Bull., 26(15):489-571, 10 pls., 7 figs., November 15. 29-1923