The discussion above demonstrates that the number of subcaudals and the ratio of tail length to total length are weak characteristics for diagnosing T. g. gracilis and T. g. hallowelli. The only remaining diagnostic characteristic given by Kirn et al. (1949) is the number of ventrals. Nevertheless, a step-cline in the number of ventrals, if one exists, is yet to be demonstrated. Therefore, we completely agree with Dowling (1957:32), who stated that "... the overlap in each character is so great that any subspecific differences appear to be as yet undefined. It is here suggested that T. gracilis be retained as binomial...."
LITERATURE CITED
Baird, S. F. and Girard, C.
1853. Catalogue of North American Reptiles in the museum of the Smithsonian Institution. Part I.—Serpents. Smithsonian Misc. Colls., 2:1-172.
Blanchard, F. N.
1938. Snakes of the genus Tantilla in the United States. Zool. Ser. Field Mus. Nat. Hist., 20(28):369-376.
Conant, R.
1958. A field guide to reptiles and amphibians. Houghton Mifflin Co., Boston, 366 pp.
Cope, E. D.