HETERODON NIGER. 65 



of Carolina and in Georgia. I have also received it from Alabama and Louisiana, 

 and there can be little doubt of its existence throughout the western country, as 

 I have Professor Troost's testimony in proof of its belonging to Tennessee. 



General Remarks. There can be no doubt that this animal was first 

 described by Catesby; later naturalists having only copied his description, or his 

 plate, which is one of the best in his work. 



Daudin and others speak of a black variety of Heterodon, which has reference 

 no doubt to this animal. I cannot, however, consider it as a variety of any 

 Heterodon, but as a distinct and separate species. It cannot be a variety of the 

 Heterodon simus, because the plates of the head are so entirely different; besides 

 it is a much larger animal. It bears more resemblance to the Heterodon 

 platirhinos; from which it differs, however, considerably, in the number of its 

 abdominal plates and in its colour, which is so constant that it must be taken as 

 an essential character in distinguishing the species. 



It differs furthermore from the Heterodon platirhinos in its habits, preferring 

 dry places; while that seems to select rocky, shady, and damp situations. 



Finally, there would appear to be a difference of geographical distribution; at 

 least in some parts of the United States. Thus, in Carolina the Heterodon 

 platirhinos is common in the upper districts of the state, and I have never 

 heard of the Black Viper being found there; while the reverse is true of the 

 sea-board: here the Heterodon niger is very common — the Heterodon platirhinos 

 seldom found. 



Vol. IV.— 9 



