438 PEOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



"Three young specimens, a male of seven years of age, two females 

 of six and four years, obtained from tlie mountains of California, near 

 Fort Mojave."* 



The next account published is the verj" meager one contained in 

 Cronise's "Natural Wealth of California," issued in 1808. The her- 

 petology of this work was outlined or written, in part or entirely, by 

 Dr. J. C Cooper. The paragraph relating to Agassiz's Tortoise is as 

 follows: " Agassiz's Tortoise (1. Xcrohates Agassizii) is found only in the 

 southeast quarter of California, which is both the driest and warmest. 

 They grow a foot in length, and live wholly on vegetable food, closely 

 resembling the tortoise called Gopher (i. e., burrower), in the Gulf 

 States. They are like that and most other species, eatable, but not 

 very well flavored." t 



The name Xerobatcs Afjasslzii alone appears again in Dr. Cooper's 

 pai^er on "The Fauna of California and its Geographical Distribution," 

 read before the California Academy, September 6, 18G9,| and also in 

 Cope's Check-list of Eeptiles, published in 1875,§ 



These descriptions and allusions, together with one other to which I 

 shall presently refer, complete, so far as I am aware, the literature of 

 the subject. As they do iiot furnish sufficient data for the identifica- 

 tion of the mature animal, I have judged it not unimportant to add a 

 description of the species, drawn from a careful study of specimens of 

 adults and young in the National ]Museum, and to point out the charac- 

 ters which separate it from Xerobatcs polyphemns. 



Description of Xerobates Aoassizii Cooper. — The shell is con- 

 siderably depressed, and nearly flat above. Its margin is serrate all 

 around, except in specimens worn by attrition with the soil, but most 

 strongly behind and in front, and is quite strongly revolute over the 

 thighs and shoulders. The center of each plate of the carapace (with 

 the exception of the marginals) is raised, forming a sort of boss; the 

 bosses of the anterior and penultimate vertebral plates are not promi- 

 nent. The vertebral plates are five in number; the anterior hexagonal, 

 the shortest side abutting against the nuchal plate; the second hex- 

 agonal, the posterior side longest; the third hexagonal, the anterior and 

 posterior sides of equal length ; the penultimate hexagonal, the anterior 

 side a little the longest; the posteriof hexagonal, the posterior side long- 

 est, the posterior angles very obtuse, making the plate api^ear almost 

 quadrilateral. The first lateral plate is irregularly heptagonal, but the 

 anterior angles arevery obtuse, so that the plate often appears to be quad- 

 rilateral or rudely triangular, with a rounded inferior side. The second 

 and third laterals are heptagonal, the lower angles as before; the fourth 

 is quadrilateral, the anterior side a little the longest. The marginal 



*Proc. Cal. Acad. Sci., ii, 1863, pp. 120, 121. 



tCronise, The Natural Wealth of California, San Francisco, 1808, p. 480. 



tProc. Acad. Cal. Sci., iv, 1873, p. C7. 



^ Coi)e, Check-list N. A. Bat. & Eept., Washington, 1875, p. 54. 



