1180 



REPORT OF NATIONAL MUSEUM, 1898. 



rated by a small plate, the posterior broad oval, separated by two 

 rather narrow plates. Three between the superciliaries, the onter large. 

 Two nasals, two loreals, one above the other. Superior labials four- 

 teen, separated from the orbit by two rows of smooth scales; inferior 

 labials thirteen; temporals smooth. Rows of scales twenty-seven, all 

 keeled, except the outer two. Gastrosteges 123, urosteges 19, the first 

 only divided. Oreidtaculnm slender, acuminate, delicate for the size 

 of the animal; joints eleven. The color above is laterally gray brown, 

 medially yellowish brown, marked by seven longitudinal series of 

 brownish black spots; these alternate; the inferior involves the tips of 

 the gastrosteges; the median embraces the largest spots, eight and 

 nine scales wide, which are occasionally subdivided, the halves alter- 

 nating. The tail is brown, crossed l»y three pairs of dark-brown bars. 



Fig. 340. 



Cbotalus polystictus Uope. 



^ 1. 



Gaanajuato, Mexico. 



Lips pale, with a spot below the pit and one behind the eye to near the 

 canthus of the mouth. A dark band convex forwards extends between 

 the eyes and is continued below the eye nearly to the labial border. A 

 pair of blackish bands form a V-shaped figure, the limbs diverging 

 over the temples, each followed by a spot; two small round spots in 

 the angle of the V, and a broad divergent band from the occiput on 

 each side of the nape. Below pale, each scute with a broad basal bor- 

 der of blackish s[)ots and punctulations. 



Length of rictus of mouth, 22.5 mm. ; breadth between eyes, 10.5 mm. ; 

 length of tail, 32 mm.; of rattle, 27 mm.; total, 593 mm. 



This elegant species has been found at Guanajuato by Dr. Duges, 

 and at other points on the Mexican plateau, and in the valley of Mex- 

 ico, but has not yet been taken within the limits of the United States. 



