A new genus of Serpents, ^r. 175 



and at present resident at La Grange, near Memphis, Tenn. 

 for the specimen of the cotton-mouth, from which this descrip- 

 tion is drawn up, and which was figured by Mr. Petit-colas 

 immediately after it was killed by spirit of wine; in which 

 delineation the colour and distinctive characters are perfectly 

 represented. 



If we may consider the arrangement of the subcaudal plates 

 in connexion with other distinctive marks, as the generic cha- 

 racter, then the reptile under consideration, forms the type of 

 a new genus, and this idea is sanctioned by other naturalists. — 

 " La presence," says Daudin, (tom. V. p. 23,) " ou absence des 

 ecailles, des plaques et des double plaques sur la peau du corps 

 et de la queue doivent invariablement servir a I'etablissement 

 des genres, et leur nombres approximatives peut offrir quelque- 

 fois un moyen auxiliaire de distinguer les especes, etc;" Ne- 

 vertheless, although this arrangement of the subcaudal plates 

 be considered as the generic character, I have hesitated to 

 consider the animal under examination as belonging to a non- 

 descript genus, till I obtained another specimen, possessing all 

 the generic characters. This, by its habits, colours, and 

 arrangement of its colours, convinced me that it must form 

 another species of the same genus. 



The general appearance of this genus is as follows :— A 

 strong, rather short, thick bod}', with a short cylindrical tail, 

 which terminates in a small horny point. The large size of 

 its head, and the small diameter of its neck, at the first glance 

 warn you of its dangerous character. In figure it resembles 

 much the crotalus; but its tail is not furnished with rattles, and 

 its head is covered with large plates as far as behind the eyes, 

 the back part being covered with small scales ; and we have for 

 diagnosis, on which this genus is established- — 



Caput ovatum a corpore distincium. 



Apertura inter nares et ocvlos. 



Tela venenifera. 



Scuta ad hasem caudct, 



ScuteJlo suh apiccm cavdrr. 

 Vol. m. 23 



