60 
room x. ij neo f pores on the under side. In some of these, 
as the common Zonurus, the tail is furnished 
with armed scales, whilst in others, as the Com¬ 
mon Cicigna, the caudal scales are unarmed. 
The American species on the contrary have 
no gland under the thighs, and the scales of 
their tail are not armed; there are several 
species of this genus, as, Burnett’s Gerrhonotus 
(Gerrhonotus Burnettii ), and the Imbricated 
Gerrhonotus (Gerrhonotus hnbricatus). 
The Scheltopusiks ( Pseudopus) have only 
rudiments of legs, in the form of undivided 
lobes, placed on the side of the vent; as in 
Durville’s Pseudopus ( Pseudopus Durvillii ) :— 
The Glass Snakes ( Ophisaurus ) are quite de¬ 
stitute of legs y as the Common Glass Snake 
(Ophisaurus ventralis') : all the species of these 
genera have the tympanum of the ear exposed. 
The Bimanae ( Chirotes ) of Mexico are sub- 
cylindrical, with small square scales, and only 
two short feeble legs, in the front of the body. 
The Double Headed Snakes ( Ampliishcenoe ) 
differ from the Bimanse in merely having no legs. 
The anterior and posterior extremities are 
equally blunt, and somewhat similar, which has 
led people to imagine, that they walk both 
backwards and forwards with the same facility 
—whence their name. 
Those ophisaurian reptiles which are de¬ 
stitute of any impressed lateral line, have been 
divided 
