120 
ON THE PHYSIOGNOMY OF SERPENTS. 
no essential change, except the introduction of some new 
genera ; on this account, we shall make our extracts from 
this last work. Cuvier having classed in the order of the 
Ophidians all reptiles without feet, it follows that beings 
of an organization different from that of serpents, such as 
the Anguis, the Pseudopus, the Csecilia, should enter into 
its formation. The first family, that of Anguis, compre- 
hends the genera Anguis, Pseudopus, Ophisaurus, and 
Acontias. The second family, that of true serpents, is 
divided into two tribes : — That of the double marchers, con- 
taining the genera Amphisbeena and Typhlops ; and that of 
the serpents properly so called, embracing all the rest of 
the Ophidians, is divided again into two sections. First 
come the innocuous serpents, distributed into the genera 
Tortrix, Boa, Coluber, and Acrochordus, genera which may 
very well be called families, and of which the majority are 
composed of several very natural subgenera : beside the 
boa figures the Scytale coronata, the Eryx, and Herpeton ; 
with the Colubri are confounded the Pythons, the Homa- 
lopsiSj^theXenopeltis, the Heterodon, the Tree-snakes, and 
the Oligodon. The venomous snakes are subdivided into 
the venomous properly so called, in which the fangs are 
isolated, and the venomous in which the dangerous wea- 
pons are followed by several solid teeth. The first of 
these two families is established for the reception of the 
Crotalus, the Trigonocephalus, the Vipera, the Naja, the 
Elaps, the Platurus, the Langaha, and several other new 
subgenera, but of too little importance to be here enume- 
rated ; the second comprehends the Bungarus, the Sea- 
snakes, and the Acrochordus, under the name of Chersy- 
drus ; the Csecilia, as a third tribe, terminates the order 
of Ophidians. In passing this classification in review, we 
shall limit ourselves to remark, that Cuvier, attaching too 
much importance to the dentary system of serpents, and 
to the form of the under scuta, departs in several respects 
from the natural system. At least, it seems to me, that 
a union such as that of Hydrophis, of Bungarus, and Acro- 
chordus, cannot be suitable to any method, natural or 
* Genus Cerberus of M. Cuvier. 
