2i2 SNAKES. 



sides likewise spotted, and the under-parts with a blackish steel-grey tinge. The 

 distinctive specific characters are the presence of a small preorbital shield on the 

 head ; the arrangement of the scales of the middle of the body in from twenty-three 

 to twenty-five longitudinal rows — these scales being smooth in the young but 

 strongly keeled in the adult — and the divided anal shield. The distributional area of 

 this snake includes the whole of Southern and South-Eastern Europe, from Lower 

 Italy and Dalmatia to Turkey, as well as Greece and the adjacent islands, and extends 

 to the interior of Asia Minor ; but there is some doubt whether the species occurs 

 in the Caucasian region. All observers are in accord that the four-rayed snake 



FOUR-RATED SNAKE (\ nat. size). 



is not only harmless but useful, since it destroys rats, mice, voles, and smaller 

 snakes. It also preys upon moles, lizards, and small birds. 

 Black-Marked Another European species of the family is the black -marked 



snake. snake {Coluber scalaris), which belongs to a separate group charac- 

 terised by the following features. The rostral shield of the head is of a large size, 

 convex, and pointed in front, while it extends backwards between the prefrontal 

 shields, where it terminates in a point. The tail is relatively shorter than in the 

 typical group. The black-marked snake, formerly separated as Rhinechis, 

 and represented in the upper figure of the illustration on p. 208 has the 

 cylindrical body relatively thick, the tail short and blunted, and the flattened head 

 broad behind and sharp in front. The body-scales, which are arranged in from 

 twenty-five to twenty -nine rows, are long, four-sided, and smooth ; the shields on 

 the under surface of the body are bent at the edges; while those beneath the tail form 

 a double series. As regards colour, there is much variation; the ground-colour 

 varying from bright grey or greenish grey, through reddish or yellowish brown, to 

 olive or reddish yellow ; while the markings of the head often take the form Of a 



