D4 COLUBEROIDEA. 
in common, that it is not easy to seize upon any sufficiently distinct and important 
to arrange them in separate genera. Thus the teeth, which are the basis of such 
arrangements in the mammalia, are here nearly similar in all—simple, solid, and 
fixed to the bones—consequently do not afford characters sufficient for classifi- 
cation. 
Other characters have, consequently, been sought, as the form of the head, 
whether distinct or not from the body—the form of the cephalic plates—the shape 
of the body—the number of abdominal plates—the form of the dorsal scales, 
whether carinated or not; the number of sub-caudal scutelle or bifid plates, ec. 
These characters, though of less consequence than those drawn from the teeth 
of mammalia, are here tolerably constant. 
In fact, it is the want of obvious determinate characters, proper for the 
establishment of genera, that has led to so much confusion in this department 
of herpetology by introducing a useless number of genera, almost as many as 
there are individuals in the family. 
