----------------+--------+--------+--------+------+---------+------ Catalogue Number|Length |Width |Length | |Diameter |Width and Collection |of |of |of |Height|of |of |carapace|carapace|plastron| |hind foot|head ----------------+--------+--------+--------+------+---------+------ USNM 60976 | 246 | 212 | 252 | 108 | 31 | 41 ----------------+--------+--------+--------+------+---------+------ USNM 61253 | 222 | 166 | 212 | 96 | 21 | 36 ----------------+--------+--------+--------+------+---------+------ USNM 61254 | 371 | 292 | 358 | 157 | 43 | 55 ----------------+--------+--------+--------+------+---------+------ IU 42953 | 281 | 220 | | | | ----------------+--------+--------+--------+------+---------+------ IU 42954 | 278 | 214 | | | | ----------------+--------+--------+--------+------+---------+------ KU 39415 | 303 | 232 | | | | ----------------+--------+--------+--------+------+---------+------ Duges (1888:146-147, and 1896:479) twice reported specimens of _Gopherus polyphemus_ from Chihuahua (see discussion of distribution); his description of two living examples (1888) agrees generally with the above description of _G. flavomarginatus_. He stated that the iris of his smaller specimen was yellow and the iris of a larger specimen brown. It will be most interesting to learn the color of juveniles of _G. flavomarginatus_. Considering the dark color of the epidermal areolae of adults, I would expect the color of hatchlings to be dark brown to nearly black, with each lamina acquiring paler borders as it grew, rather than acquiring darker borders as is usually the case in _G. berlandieri_ (personal observation), _agassizii_ (Miller, 1932:194, pl. 2; Woodbury and Hardy, 1948:165, figs. 9 and 10), and _polyphemus_ (personal observation). [Illustration: PLATE 7 PLATE 7. _Gopherus flavomarginatus_ new species: _Top_--Dorsal and ventral views of holotype (× 1/3); _Middle_--Lateral view of holotype (× 1/3); _Bottom_--Head of paratype (USNM 61254) (× 1/2) and antebrachium of holotype (× 5/6). Dark outline on plastron of holotype indicates where portion of shell was removed (and then replaced) in course of preparation.] [Illustration: PLATE 8 PLATE 8. _Gopherus flavomarginatus_ new species: Dorsal views of paratypes (from top to bottom, IU 42953, IU 42954, and KU 39415), approximately 1/5 natural size.] [Illustration: FIG. 1. _Gopherus flavomarginatus_ new species: 1a and 1b--Lateral and ventral views of skull of holotype (× 1); 1c--Cross section of paratype (USNM 60976) taken through middle of third central lamina (× 2/5).]