152 colubrim; 



Genus TROPIDONOTUS, Kuhl 



Maxillary teeth increasing in size posteriorly. 

 Head more or less distinct from neck ; eye moderate 

 or rather small, with round pupil. Body more or 

 less elongate ; scales keeled, with apical pits. Tail 

 moderate. 



This large genus, comprising about ninety species, 

 and of almost cosmopolitan distribution, with the 

 exception of South America and the greater part of 

 Australia, may be divided into several subgenera, two 

 of which are represented in Europe — Tropidonotus 

 proper, with the common T. natrix, and Nevodia, 

 Baird and Girard, with two closely related species 

 of more thoroughly aquatic habits, T. tessellatus and 

 T. viperinus. 



3. Tropidonotus natrix, Linnaeus 



[Natrix vulgaris, Laurenti ; Coluber torquatus, 



Lacepede) 



The Grass-Snake, or Ring-Snake 



Form.— Moderately slender; snout short, obtuse, 

 not prominent ; eyes and nostrils lateral, the former 

 moderately large. Tail four to six and a half times 

 in the total length. 



Head-Shields. — Rostral broader than deep, visible 

 from above. Nasal divided, very rarely semidivided. 

 Internasals at least as broad as long, trapezoid, 

 shorter than the prefrontals. Frontal broader than 



