128 RHINOSTOMA COCCINEA. 
The rostral plate, though prolonged in both, is of very different form, and is 
carinated above in Heterodon, and not in Rhinostoma; even in their teeth 
they are not much more allied to Heterodon than to Tropidonotus. 'The 
posterior large maxillary teeth are much more erect here than in either of those 
genera. 
In short, then, their whole ‘“physionomie” in life is different. The small head— 
the slightly projecting superior orbital plates—the small eyes—give the Rhinos- 
toma coccinea a mild and placid look, which really appertains to its character; 
while the broad, flattened head—the projecting superior orbital plates, like the 
Crotaloidea, gives an Heterodon the look of a bold, blustering fellow, as he is. 
