OE THE OPHIDIANS IN GENERAL. 
It is usual to comprehend under the denomination of 
Serpents, all those reptiles which, along with a total want 
of extremities, have a very elongated form of body. A 
more rigorous examination, however, demonstrates, that 
among animals which on such principles it would be ne- 
cessary to class with serpents, some present, in their general 
organization, peculiarities that separate them in every re- 
spect from serpents, to which they bear no resemblance, 
except in their lengthened forms. It was reserved for our 
times — thanks to the researches of the anatomist ! — to ar- 
range among Batrachians some of those anomalous beings, 
the greatest part of which have been jumbled together in our 
systems. In casting a rapid glance over the great series 
of reptiles whose bodies are covered with scales, we dis- 
cover that these animals, with the exception of the tortoises, 
are modelled on two types, familiarly known by the desig- 
nation of Saurians and Ophidians. But in comparing 
these animals with each other, we perceive that the more 
or less elongated body exists in them in every degree 
that the development of the extremities diminishes in pro- 
portion as the species to the second type ; that the function 
of the ribs, as organs of locomotion, augments in the same 
degree ; that species much allied present sometimes great 
disparities in the arrangement of the extremities, or even 
are only distinguishable from each other by the want or 
presence of extremities ; t in a word, that the function 
^ The Scinks, the Seps, the Pygodactylus, the Monodactylus, the 
Pygopus, the Chalcis, the Tetradac(ylus, the Ophisaurus, the Pseudo- 
pus, &c. 
t The Amphisbaena and the Chirotes. 
