70 HETERODON PLATIRHINOS. 
annulatus of Troost* is only a variety of this, for it is not uncommon to see 
individuals more or less annulated. 
GeneraL Remarks. There can be no doubt that this is the Heterodon 
platirhinos of Latreille, from his description, as well as from the geographical 
distribution he gives it. ‘This species of Heterodon is found in New Jersey, 
where Palisot de Beauvais first observed it, and from which state the animal 
here described was also received. 
It seems to me very clear that we have three species of Heterodon in the 
Atlantic states—Heterodon platirhinos, Heterodon niger, and Heterodon simus— 
which latter differs in several respects from the two former; as in size, in having 
the neck smaller, in colour and markings, in the form of the rostral plate, and 
in having the azygous plate between the anterior frontal plates surrounded with 
small scales; as well as in being confined to the southern and western states. 
The animals of this genus have the power of flattening the head and body still 
more than in that of Tropidonotus; in which respect they approach the Cobra de 
Capello of India.t 
* Ann. Lye. N. Y., vol. iii. p. 188. 
+ See anatomical part of this work for an account of this structure. 
