| fee) REPTILES AND BIRDS. 
the two genera Circosaura and Lepisoma—of which the first com- 
prises some two or three species only. All of these reptiles have 
exceedingly long tails, though not so inordinately long as in the 
Lacertide of the genus Zachydromus. 
Certain other families have a distinct longitudinal fold, covered 
with small granular scales on each side. ‘These are the families 
Chaleidta, Holaspide, and the more extensive one of Zonuride. 
The Chalcide have the head covered with regular many-sided 
shields, and the lateral fold is indistinct ; limbs small and rudi- 
mentary, and the hind feet are undivided in the genera Chadcis and 
Bachia, with three tubercles in place of toes in Mzcrodactylus, and 
with four clawed toes in Brachypus. Each of these genera is 
founded on a single species, and all are doubtless peculiar to the 
New World. The Ao/aspide is also founded on one species only, 
the Holaspis Guenthert, which again 1s supposed to be South 
American. It has four well-developed limbs, a double row of 
plates along the back and upper surface of the tail, and the latter 
organ is curiously serrated laterally. 
The Zonuride constitute a considerable family, to which some 
eighteen or twenty genera are assigned, and which present consider- 
able modification of form. The ears are distinct, whereas, in the 
Chalcide they are hidden under the skin. ‘The head is pyramidal, or 
depressed, and covered with regular many-sided shields ; eyes with 
two valvular lids. Limbs mostly well-developed, but short in some, 
and rudimentary, or even wanting, in the so-called Glass Snake which 
constitute the sub-family Pseudopodine. ‘There is no external 
trace of them in the North American Glass Snake, Ophisaurus ven- 
tralis; and in the Old World genus, Psewdopus, there is only one 
pair, posterior, rudimentary, and undivided. These Reptiles are long, 
and serpentiform in shape; whilst in other Saurians the whole skin 
of the belly and of the sides is extensible, the extensibility is limited 
in the Glass Snakes to a separate part of the skin; and, as Dr. 
Giinther remarks, ‘the scaly covering of the upper and lower parts 
is so tight that it does not admit of the same extension as in Snakes 
and other Lizards; and the Psewdopus, therefore, could not receive the 
same quantity of food in its stomach as those animals, were it not for 
the expansible fold of the skin running along each side of its trunk.” 
One species of Pseudopus, the P. Pallasiz, inhabits Asia Minor and the 
south-east of Europe ; and there is another, P. gracz/is, in the Indo- 
Chinese countries (or those lying eastward of the Bay of Bengal). A 
second sub-family, Gerrhonotine is peculiar to America, and consists 
of more ordinarily-shaped Lizards, which are ranged in four genera. 
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