40 NATURAL HISTORY. jjJPPER FLOOR. 
iralis) : all the species of these genera have the tympanum 
of the ear exposed. 
The Bimanse ( Chiroies ) of Mexico are subcylindrical, 
with small square scales, and only two short feeble legs 
placed in the fore part of the body. The Amphisbsense 
differ from the Bimanse in having no legs. The anterior 
and posterior extremities are equally blunt, and somewhat 
similar, which has led to the idea that they walk both 
backwards and forwards with the same facility—whence 
their name. 
Those ophisaurian reptiles which are destitute of any 
impressed lateral line, have been divided into several groups, 
as the True Seines ( Scinci ), having four legs, w T ith small 
margined toes, and a sharp edged muzzle, which enable 
them to bury themselves with facility in the sand of the 
deserts they inhabit. 
Others have blunt noses, thin smooth scales, and long 
conical tails ; as the New Holland Tiliqua (Lacerta scin- 
coides); the Ribbon Galley-Wasp ( Lac . tceniolata) from 
New Holland ;—one of the New Holland kind, however, 
(Trachydosaurus rugosus,) has large rugose bony scales, 
and a short depressed tail. 
Some of the Seines ( Lygosomata ) have very long slender 
bodies, and very small, weak feet; as the Short-footed 
Lygosoma (a Scincus bracliypus), and the dotted Lygosoma 
(L. punctatum). 
The common Seps (S. cJialcides) } from the South of 
Europe, the form of whose body is nearly similar to that of 
the Seines, has only three toes on each foot; in the Lacer- 
tine Siaphos ($. cequails) the ears are concealed under 
the skin. 
The Bipes are peculiar for having only two oblong lobes 
in the place of legs. One of the species, the Brazilian 
Bipes (Pygopus cariococca ), has the tympanum hid under 
the skin, whilst in the New Holland species, Fraser’s Bipes 
( Dehna ), the ears are as distinct as in the Seines. 
The Blind-worms ( Angues) have scales- like the Seines, 
but only rudiments of legs concealed beneath the skin. 
Cases 6—13 contain the Serpents, animals without 
legs, but with mouths capable of such extraordinary dilata¬ 
tion, in consequence of the peculiar mode by which the 
