Mr. Bogert further related that, in 1946 when he was camped at Las Delicias, Coahuila, a Mexican mule herder told him of seeing a large tortoise "three bolsons north" of the bolson in which Las Delicias is located (the general area referred to would be near Americanos). The man awoke one morning to find his saddle missing; following tracks from the place where the saddle had been left, the man eventually found it on the back of a large tortoise. The tortoise had apparently sought shelter beneath the saddle and, finding it unsatisfactory, had walked away with the saddle on his back.

Either of the incidents related above, or the reference of Duges (loc. cit.) to large size, since they are based on second or third-hand accounts, would seem to be unrealistic and of little scientific value when considered alone and at face value. However, in the light of the discovery of Gopherus flavomarginatus, these accounts have new meaning and tend to support my proposal that the species is the largest tortoise in North America.

Remarks.—The paratypes at the University of Illinois were found in a trash-dump in Carrillo. According to what the collectors learned from local inhabitants, the species is used for food and the shells are sometimes used for poultry dishes or even for eating utensils. Although the species is found on the flat, sandy desert near Carrillo, it is more common on the nearby mountain slopes and is seen there most frequently after rains. Dickerman (field notes, 1954) likewise noted that the species was eaten near Americanos; the K.U. paratype represents the best (and only specimen saved) of several broken shells found in that area. Judging by the habits of other members of the genus and by the notes of Duges (1888:147), G. flavomarginatus is probably herbivorous.

Acknowledgments.—A portion of this study was completed in the summer of 1958, while I was an internee at the United States National Museum. I am grateful to Dr. Doris M. Cochran of that institution for helpful information regarding the origin of the type and for permission to study other specimens in her care. Thanks are due also to Messrs. Pete S. Chrapliwy and Kenneth L. Williams who collected two of the paratypes and who generously provided their notes on the specimens when learning of my study, to Dr. Hobart M. Smith and Mr. Charles M. Bogert for offering helpful suggestions and for the loan of specimens, and to Mr. Jebb Taylor for assistance with taking data. The drawings are the work of Mrs. Connie Spitz; the photographs are by the author.

LITERATURE CITED

Carr, A.
1952.Handbook of turtles; the turtles of the United States, Canada, and Baja California. Cornell Univ. Press, xv + 542 pp., 37 figs., 82 pls., 15 tables, 23 maps.
Duges, A.
1888.La Tortuga Polifemo. La Naturaleza, 1(ser. 2):146-147.
1896.Reptiles y Batracios de los E. U. Mexicanos. La Naturaleza, 2(ser. 2):479-485.
Fenneman, N. M.
1931.Physiography of western United States. McGraw-Hill, New York, 1st. ed., v-xii + 534 pp., 173 figs.
Miller, L.
1932.Notes on the desert tortoise (Testudo agassizii). Trans. San Diego Soc. Nat. Hist., 7:187-208.
Smith, H. M.
1949.Herpetogeny in Mexico and Guatemala. Ann. Assn. American Geographers, 34(3):219-238, 1 fig.
Thayer, W. N.
1916.The physiography of Mexico. Journ. Geol., 24:61-94, 2 figs.
Woodbury, A. M., andHardy, R.
1948.Studies of the desert tortoise,Gopherus agassizii. Ecol. Monogr., 18:145-200, 25 figs., 4 tables.

Transmitted November 18, 1958.