SNAKES OF THE GENUS PITUOPHIS 217 



Nelson, Julius. 



1890. A descriptive catalogue of the vertebrates of New Jersey. Geol. Surv. 

 New Jersey, Final Rep. State Geol., vol. 2, pt. 2, pp. 487-786. 



NOTESTEIN, F. N. 



1905. The Ophidia of Michigan. 7th Ann. Rep. Michigan Acad. Sci., pp. 

 112-125. 

 Ortenburgfr, Arthur Irving. 



1925. A preliminary list of the snakes of Oklahoma. Contr. Zool. Lab. 



Univ. Oklahoma, ser. 2, No. 55, pp. 84-87. 



1926. Reptiles and amphibians collected in the Wichita Mountains, Co- 



manche County, Oklahoma. Copeia, No. 155, pp. 137-138. 

 1927a. A report on the amphibians and reptiles of Oklahoma. Contr. 



Zool. Lab. Univ. Oklahoma, ser. 2, No. 63, pp. 89-100. 

 1927b. A key to the snakes of Oklahoma. Proc. Oklahoma Acad. Sci., pt. 1, 



vol. 6, pp. 197-218. 

 1927c. A list of reptiles and amphibians from the Oklahoma Panhandle. 



Copeia, No. 163, pp. 46-48. 

 1928. The whip snakes and racers: Genera Masticophis and Coluber. Mem. 



Univ. Michigan Mus., vol. 1, xviii + 247 pp., 64 figs., 36 pis. 

 1930. A key to the lizards and snakes of Oklahoma. Publ. Univ. Oklahoma 

 Biol. Surv., vol. 2, No. 4, pp. 209-239, 44 figs. 

 Obtenburger, Arthur Irving, and Freeman, Beryl. 



1930. Notes on some reptiles and amphibians from western Oklahoma, 

 Publ. Univ. Oklahoma Biol. Surv., vol. 2, No. 4, pp. 175-188, maps. 

 Obtenburger, Arthur Irving, and Ortenburger, Roberta D. 



1927. Field observations on some amphibians and reptiles of Pima County, 



Arizona. Contr. Zool. Lab. Univ. Oklahoma, ser. 2, No. 64, pp. 



102-121. 

 Over, William Henry. 



1923. Amphibians and reptiles of South Dakota. Bull. Univ. South Dakota, 



ser. 23, No. 10, 134 pp., 18 pis. 

 Pack, Herbert J. 



1919, Note on food habits of the bull snake. Copeia, No. 68, p. 16. 

 Pope, T. E. B. 



1925. A two-headed snake. Yearb. Publ. Mus. Milwaukee, vol. 5, pp. 161- 



167. 

 Pope, T. E. B., and Dickinson, W. E. 



1928. The amphibians and reptiles of Wisconsin. Yearb. Publ. Mus. Mil- 



waukee, vol. 8, No. 1, 138 pp., 21 pis. 

 Pratt, Henry Sherring. 



1923. A manual of the vertebrates of the United States, 422 pp., 183 figs. 

 Philadelphia. 

 Proctor, Jean B. 



1920. On the variation in the number of dorsal scale rows in our British 



snakes. Proc. Zool. Soc. London, 1920, pp. 357-364, 3 figs. 

 Richardson, C. H. 



1915. Reptiles of northwestern Nevada and adjacent territory. Proc. U. S. 

 Nat. Mus., vol. 48, pp. 403-435. 

 Roddy, Harry Justin. 



1928. The reptiles of Lancaster County, and the State of Pennsylvania 

 (Dept. Nat. Hist. Franklin and Marshall College), 53 pp., figs. 



