XENOSAURUS.—HELODERMA. 43 
Fam. XENOSAURIDZ. 
XENOSAURUS. 
Cubina sp., Gray, Ann. & Mag. Nat. Hist. 1856, xviii. p. 270 
Xenosaurus, Peters, MB. Ak. Berl. 1861, p. 453. 
1. Xenosaurus grandis. 
Cubina grandis, Gray, 1. c. 
Xenosaurus fasciatus, Pet. 1. c. 
Xenosaurus grandis, Cope, Proc. Ac. N. Se. Phil. 1866, p. 8322; Bocourt, Miss. Sc. Mex., Rept. 
p- 803, t. 20 F. figg. 1. 
Hab. Mexico, Cordova and Oaxaca (Sallé), Huanusco (Peters), Orizaba, rare in the 
alpine region (Sumichrast). 
Fam. HELODERMATIDA. 
HELODERMA. 
Heloderma, Wiegmann, Isis, 1829, p. 627. 
1. Heloderma horridum. (Tab. XXVI.) 
Acaltetepon, Hernandez, Hist. Nov. Hispan. p. 315. 
Heloderma horridum, Wiegm. 1. c.; and Herp. Mex. p. 24, fig. 1; Wagl. Ic. Amphib. fasc. 2; 
Troschel, Arch. Naturgesch. 1853, p. 294, tt. 138 &14; Sumichrast, Bibl. Univ. xix. 1864, 
p- 45 (Ann. & Mag. N. H. 1864, xiii. p. 497) ; Kaup, Wiegm. Arch. 1864, p. 33, t. 3. figg. 1-2 ; 
Gervais, Journ. Zool. 1878, p. 458, t. 12. figg. 4-8; Sumichrast, Compt. Rend. 1875, Ixxx. 
p- 676, and Bull. Soc. Zool. Fr. 1880, p. 178; Bocourt, Miss. Sc. Mex., Rept. p. 297, tt. 208 
& 204; Fischer, Verh. Ver. Hamb. v. pp. 2, 16. 
Hab. Muxtco, Presidio, near Mazatlan (Forrer), Sinaloa (Bocourt), Guanajuato (Dugés), 
Tapana, Tehuantepec (Sumichrast). 
“‘Escorpion ” of the Mexicans ; “ Talachini” of the Zapotec Indians. 
The external and anatomical characters of this most interesting Lizard have been 
fully described and the poisonous nature of its bite proved beyond doubt. Adult specimens 
vary more or less in coloration; and it is therefore of interest to ascertain the normal 
type, as it appears in the young; the more so, as this species seems to constantly differ 
in this respect from its short-tailed northern congener. The size and division of the 
plates or scales also vary in the adult. 
The young specimen figured here of the natural size is from Tapana. It is black, 
with yellow spots and bands. The head is entirely black ; a series of five or six yellow 
angular spots along the median dorsal line, each with a brown margin. Sides of the 
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