2566 



SCALED REPTILES 



The keel-tailed snake (Helicops carinicauda) inhabits Brazil. It attains a 

 length of between three and four feet, and is characterized by having the scales on 

 the back of the head smooth, and those on the body keeled and arranged in nine- 

 teen rows, the frontal shields being nearly or quite as long as the parietals, while 

 there are from one hundred and twenty-six to one hundred and fifty-five shields on 

 the lower surface of the body. The general color is dark olive brown above, with 

 four more or less distinctly-defined blackish stripes, and a yellow stripe along the 

 two lower rows of scales; on the under parts the ground color is yellow or red, with 

 black spots or stripes on the body, and a black stripe on the tail. In the neighbor- 

 hood of the Rio Grande do Sul this species is one of the commonest of snakes; and 

 while its general habits appear to be very similar to those of the water snakes, like 

 all the other members of its genus, it produces living young. 



KEEL-TAILED SNAKE. 

 (One-half natural size.) 



The snakes we have now to consider, while still belonging to the 

 Pygmy Snakes ty p ical SUD family of the solid-toothed series, differ from the foregoing 

 in that inferior spines are developed only in the vertebrae of the anterior half of the 

 backbone, and are further characterized by the nasal bones being fully as large as 

 the prefrontals. The preceding group are more or less aquatic in their habits, but 

 those of the present assemblage are terrestrial or arboreal. The pygmy snakes have 

 the hinder borders of the shields on the lower surface of the body entire, the front 

 lower teeth larger than the hinder ones, the eyes relatively small, and no internasal 

 or temporal shields on the head. The head is not distinct from the neck, each nos- 

 tril is pierced in a very small nasal shield, the body is cylindrical with the smooth 



