Amphisbaenia
Amphisbaenians, also called "worm lizards", are little-known burrowing
reptiles that typically have no legs. Their tails resemble their heads,
giving them a somewhat two-headed appearance.
Amphisbaenia is a suborder of reptiles within the order
Squamata, which also includes lizards and snakes. Like their
amphibian counterparts the caecilians (order Gymnophiona),
amphisbaenians are adapted to a fossorial niche. They burrow and are
carnivorous, eating insects, worms, and in captivity many eat small rodents.
Their skulls contain more bone tissue than those of lizards, and their
eyes are often small or absent. The left lung is larger than the right (asymmetry in the lungs is a
point of anatomy they share with the snakes and caecilians), and their
bodies appear segmented like earthworms, as the scales form rings called
annuli.
The amphisbaenians are all limbless with the exception of the family
Bipedidae, whose members have small front limbs. Amphisbaenians are
typically red or pink.
Amphisbaenians are found in tropical areas in Central
and South America, Africa, and parts of Europe and Asia. They are
almost never to be seen in the pet trade or in zoos. Sadly, they are rarely
studied and little is known about them.
References and further reading:
http://www.nafcon.dircon.co.uk/amphisb1.html
photo:
http://www.angelfire.com/mo2/animals1/reptile/amphisbaena.html
http://listproc.ucdavis.edu/archives/herp-l/log0011/0000.html
http://museum.nhm.uga.edu/gawildlife/reptiles/squamata/amphisbaenia.html
diagrams:
http://www.curator.org/LegacyVMNH/WebOfLife/Kingdom/P_Chordata/ClassReptilia/O_