TROPIDONOTUS 167 



ocellar. Specimens with ocellar vertebral spots are 

 found also in Sardinia and in Spain. 



As in T. natrix, there occur, in the South of 

 France, in Sardinia, in the Spanish Peninsula, and 

 in North Africa, specimens with two light yellow 

 or reddish lines along the back (Plate III., third 

 figure), in addition to the usual markings (C. auro- 

 lineatus, Gervais, T. chersoides, Dumeril and Bibron). 



Melanism is rare in this species, only one specimen 

 being known, from Nantes in Southern Brittany; 

 uniform black, with the exception of a few white 

 spots on the belly. A remarkable variety (var. 

 incertus, Fatio), connecting this species with the 

 preceding, occurs in Switzerland near Geneva. Not 

 only is its coloration sometimes very similar to 

 that of T. tessellatus, but it agrees with it in the scales 

 being often disposed in nineteen rows instead of 

 twenty-one, and in the presence of eight upper 

 labials, fourth or third and fourth entering the eye ; 

 however, the frequent presence of ocellar spots 

 on the sides, and the low number of ventral shields 

 (147 to 151), show that it should be referred to 

 T. viperinus. 



Size. — Rarely reaches a length of 3 feet in Europe, 

 the largest specimens being from Sardinia. An 

 Algerian specimen 3 feet 3 inches long is on record. 



Distribution. — France as far north as Southern 

 Brittany, the Forest of Fontainebleau, and the 

 Department Aube, the whole of the Spanish Penin- 



