SNAKES 
According to legend, the entire serpentine population of Ireland fell vic¬ 
tim to the doughty shillelah of St. Patrick. Be that as it may, there really 
are no snakes in Ireland. New Zealand, and a few isolated oceanic islands 
of recent formation such as the Azores, must have had their St. Patricks, 
too, for these regions are also snakeless. However, with these exceptions, 
all parts of the temperate and tropical world have representatives of the 
twenty-three hundred existing species of snakes. 
As a rule the snakes that come most often to the attention of people 
are those noted for some spectacular habit or feat—real or fictitious. Con¬ 
sequently snakes, for the average reader, are things that drop out of trees 
to strangle men in their coils, and creep into tents and houses in India 
to kill people with their poisonous fangs. There are snakes that can do 
these things, in tropical America as well as India. But the great majority 
are not only harmless in their dealings with man but even help him to 
control rodent and insect pests. 
The large snakes, such as pythons and boas, are not the only ones 
capable of swallowing prey many times their own girth. All snakes can 
perform this feat because their jaws readily spread both at the hinges and 
at the front where the two halves of the lower jaw are held together with 
an elastic ligament, unlike the fixed jaws of lizards. Legless lizards should 
not be confused with snakes. 
Contrary to popular opinion snakes have good vision. Tests made by 
Warkentin show that sight is temporarily disturbed just before they shed 
their skins, because the cornea becomes opaque until the skin is sloughed 
off. Just after shedding, the sight is keenest. 
For convenience the ten families of snakes have been grouped in the 
following popular classification: 
Worm-like Snakes are small, harmless creatures, seldom seen because 
of their burrowing habits. They include about one hundred species of 
blind, blunt-tailed and shiny-scaled typhlopids found in almost all tropical 
countries; the twenty-five closely related leptotyphlopids (sometimes called 
glauconids) of the warmer regions of the Americas, southwestern Asia and 
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