54. GOPHERUS 987 
movably united to the carapace by a broad bridge. There is 
a ridge along the middle of the alveolar surface of each 
side of the upper jaw parallel to the cutting edge, except in 
front where there is a longitudinal ridge at the symphysis. 
The internal openings of the nostrils are between the eyes. 
The limbs are club-shaped, the fore limbs flattened, without 
webs. The skin on top of the head is divided into scales. 
There is but one supracaudal plate. 
Of the three known species one occurs within our limits. 
The genus is but doubtfully distinct from Testudo. 
228. Gopherus agassizii (Cooper) 
Desert Tortoise 
Plates 125, 126, and 127 
Xerobates agassizit Cooper, Proc. Cal. Acad. Sci., Vol. 2, 1863, p. 120 
(type locality, Mountains of California near Fort Mojave); 
Cooper, Proc. Cal. Acad. Sci., Vol. IV, 1870, p. 67; True, Proc. 
U.S. Nat. Mus., Vol. 4, 1881, p. 437; TRue, Bull. U. S. Nat. Mus., 
No. 24, 1883, p. 38. 
Testudo agassizii Boutencer, Cat. Chelonians Brit. Mus., 1889, p. 
156; Dirmars, Reptile Book, 1907, p. 69, pl. XXIV; SrEBENROcK, 
Zool. Jahrb., Suppl. 10, Heft 3, 1909, p. 517; Camp, Univ. Cal. 
Publ. Zool., Vol. 12, No. 17, 1916, p. §12; GrinneLit & Camp, Univ. 
Cal. Publ. Zool., Vol. 17, No. 10, 1917, p. 199; Cowxes, Journ. 
Entomol. & Zool., Pomona College, Vol. XII, No. 3, 1920, p. 64; 
Terron, Mem. y Rev. Soc. Cient. Antonio Alzate, Vol. 39, 1921, 
p- 165. 
Gopherus agassizii SreEJNEGER, N. Amer. Fauna, No. 7, 1893, p. 161; 
Van Densurcu, Occas. Papers Cal. Acad. Sci., V, 1897, p. 353 
Mc Law, Critical Notes, 1899, p. 2; Meek, Field Columbian Mus., 
Zool. Series, Vol. 7, No. 1, p. 3; VAN Densurcu & Stevin, Proc. 
Cal. Acad. Sci., Ser. 4, Vol. 3, 1913, p- 397; STEJNEGER & Barsour, 
Check List N. Amer. Amph. Rept., 1917, p. 121; Van DenBuRGH & 
SLEvIN, Proc. Cal. Acad. Sci., Ser. III, Vol. XI, 1921, p. 29. 
Description.—Shell broad and deep, often flattened 
above, its margin serrate all around, except in worn speci- 
