Occasional Papers of the Museum of Zoology 3 



the upper from tlie occipital region, inclosing a broad, dark 

 brown band. Dorsal region ligbt reddish brown with a poorly 

 defined and lighter vertebral stripe. 



^Measurements. 



Total length T,2y mm. 



Length of head and body 96 mm. 



Length of head to posterior margin of ear. . 2/ mm. 



Length of tail 23 1 mm. 



Width of head 2/ mm. 



Azotes on Paratypcs: Sixty specimens of this form liave 

 been examined, and in forty-live of these the width of the 

 parietal plates was measured. In every specimen the width 

 of the parietal plates is equal to the width of the head between 

 the superciliaries at the third supraocular plate, and the outer 

 parietals on each side are in contact with the enlarged post- 

 orbital scale or separated from it bv one or rarely two scales, 

 average in forty-five specimens 1.08. Five of the largest 

 males vary from 88 mm. to 100 mm. in length, exclusive of 

 tail, average 93.5 mm., and four of the largest females range 

 from 69 mm. to 8r mm. in length, average 76.2 mm. The 

 number of femoral ])ores in forty-four specimens varies from 

 16 to 24, average 20.2. 



Remarks : The series of specimens from Colombia has 

 been compared with a series of sixty-four specimens from the 

 sand ridges on the Demerara River, about thirty-five miles 

 from Georgetown, British Guiana, with the following result. 



In forty-eight specimens from Guiana the width of the 

 parietals is decidedly narrower, being about equal to the dis- 

 tance between the outer margins of the first supraorbital 

 plates, and the outer parietal plates are separated from the 

 enlarged postorbital scales by from two to four scales, average 



