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 platirhines 
seldom found, 
Vor. [V.—9 
