21 



as in the E. murinus, the head, in fact, being more depressed. The 

 scales are not so numerous. Boulenger gives (1. c.) fifty-seven to sixty- 

 three rows in the E. murinus. The type specimen of the E. notwus has 

 forty-five rows; one of the Argentine skins has forty-five rows and two 

 others have forty-eight. 



The coloration is distinct. Thus there is a black band from the 

 eye to the angle of the mouth, and the top of the head is lead-color, 

 with a dark border in the E. murinus, In E. notaeus, besides the black 

 band from the eye, there are three similar ones on the top of the 

 head; two superciliary, which meet on the muzzle, and one median. 

 The dorsal spots are more numerous and are closer together in the 

 E. notaeus. In two of the skins I count fifty-three and sixty spots, re- 

 spectively, of which the anterior are confluent into a median stripe. 

 In an E. murinus, which I owe to the Zoological Society of Philadel- 

 phia, there are only forty-seven spots, and these are well separated, 

 especially anteriorly. There are two rows of eye-like spots on each side 

 in E. notaeus for most of the* length, or until their superior borders 

 become confluent into two longitudinal stripes on each side, which ex- 

 tend to the head. In the E. murinus there are two rows of such spots 

 on the posterior part of the body only, and the single row does not 

 become confluent into a stripe anteriorly. There are two rows of 

 small broken black spots below these in both species. In a word, the 

 color difference between the two species consists in the fact that the 

 spots are more numerous in the Southern species and become confluent 

 into stripes anteriorly, which they do not in the Northern species, where 

 they become smaller and tend to disappear. The ground color in the 

 Paraguayan species is brown, in the E. murinus it is lead-color. 



The largest skin of the E. notwus measures 2,519 mm., of which 

 the tail is 324 mm. 



