EEPTILIA. 271 



niger Mekr., and lias been confounded with Trigonocephalus or Cencltris 

 Moheson. Usually the first two species are regarded as varieties, but HoL- 

 BROOK considers that they ought to be distinguished as species. 



Helicons Wagl. (in part), DuM., Bibk. Head scarcely broader 

 than trunk, covered with small scutes, with anterior frontal scute 

 unpaired. Eyes placed at the anterior and upper part of head. 

 Nostrils perforated in the nasal scute towards its upper part. Two 

 last upper maxillary teeth rather more remote from the rest, larger. 

 Scales carinate. Tail moderate. 



Sp. Helicops carinicaudus Wagl., Homalopsis carinicattda Schl., Coluber 

 carinicauda Maxim. Pr. v. Wied, Abb. zur Naturgesch. Brasil. Lief. xi. ; — 

 Helicops angidatus Wagl., Homalopsis angidatus Boie, Schleg. Species 

 from South America, analogous to Homalopsis, but without a groove on the 

 large hinder tooth of the upper jaw. 



Tropidonotus Kuhl, Wagl. Head distinct from trunk, ovato- 

 oblong. Gape of mouth ample. Some posterior teeth in upper 

 jaw longer than the rest, which are moderate, equal. Posterior 

 ocular scutella mostly three. Scales all or the most carinate. 



These serpents deserve in the proper sense the name of Amphibia, and 

 many seem to prefer a residence in water to that on land. They live on 

 fishes, frogs, &c. Species of this form are found in the temperate and warm 

 countries of the ancient world and in North America. 



Sp. Tropidonotus torquatus mihi, Coluber Natrix L., Van Lier 1. 1. Tab. i. 

 Sturm Deutschl. Fauna, AmpMb. Heft iii. ; the ringed snake, la Couleuvre 

 a collier, die Ringelnatter, &c. ; the tail forms nearly one-fifth of the whole 

 length, and has commonly between 48 and 68 pairs of scutes; the 

 abdominal scutes are about 1 70 ; there is a whitish-yeUow collar behind the 

 head ; the back is greyish-green, the belly white, with black spots. There 

 are however many varieties of colour in this species ; sometimes it is almost 

 quite black. The ringed snake attains a length of 3' ; it pairs in June and 

 July, and lays its eggs, about 30 in number, in tlie autumn, on dunghills 

 and in sheepfolds ; it hides underground in winter, in mole-runs, &c. This 

 species is found in almost all the countries of Europe. — Tropidonotus 

 vittatus, Coluber vittatus L., Mtts. Ad. Frid. Tab. 18, fig. 2; Bechst. 

 Naturgesch. d. Amphib.iv. Taf. 10; at Java, &c. 



Note. — In some species there is a space without teeth in the upper jaw in 

 front of the two or three larger ones. Such are placed by Dumeril and 

 BiBEON in a separate Genus Amphiesma, Sp. Tropridonotus stolatus, Coluber 

 stolatus L. ; and some others ; all belonging to the East Indies and the 

 oriental parts of Asia. 



Rachiodon JoURDAN, Deirodon OwEN. Teeth small, few in 

 the posterior part of jaws; palatine few, very small. Inferior 



