184 THE VIVARIUM. 
oviparous. These Reptiles are most numerous in the hottest parts 
of the world ; and there, both their size and variety is greatest. In 
the temperate latitudes they hibernate. Dr. Giinther says that “ the 
limits of their distribution seem to be the 70th parallel N. lat. in 
Europe, the 54th in British Columbia, and the 40th parallel 
S. lat. in the Southern Hemisphere.”’ The same great authority 
on these matters also says that ‘‘ Snakes are 
the most stationary of all Vertebrates; as 
long as a locality affords them a sufficiency 
of food and some shelter to which they can 
retreat, they have no inducement to change 
it. Their dispersal, therefore, must have 
been extremely slow and gradual.” This 
seems to be one of the reasons why Snakes, 
when preperly treated, do so well in 
captivity. As the shape and arrangement 
of the head-shields are of great use in 
distinguishing the various genera and spe- 
cies, and as these shields will be frequently 
referred to in describing the different 
Fig. 59. — DIAGRAM 
showing the Position Snakes, I have ventured to show, by means 
a ee Principal of Figs. 59, 60, and 61, their position and 
aa 
(Elaphis quaterradi- The Blind Snakes (Z'yphlopide) are small. 
atus), from nature: : : : : 
1, Rostral; 2, Anterior burrowing Reptiles, which possess a ecylin- 
eae t Wectial: drical body of almost a uniform thickness 
ee epee oe throughout. They are covered with smooth 
Temporal. tiled scales, all of about the same size 
and shape. Their stiff polished bodies are 
well adapted for burrowing purposes. Their eyes, as their name 
implies, are very small or only rudimentary, by means of which, 
at the most, some of them have only a perception of light. They 
are protected from damage while burrowing in the earth by the 
ocular and pre-ocular shields which cover them, and which are 
more or less transparent. The front part of their head is 
covered with large shields. Their blunt conical tail is short, 
strong, and slightly bent. There are a few teeth in the upper 
jaws, none on the palate or in the mandibles. The head is small 
