IHBERNATION AND SLOUGHING. 63 
different species is said to vary, that of the smooth 
snake being less than that of the adder! Dr Opel 
observed that the hibernation of the smooth snake 
was neither so prolonged nor was the degree of tor- 
por so great as in some other serpents. This snake 
exhibits another interesting peculiarity, in that in- 
stead of covering itself up in holes and corners it 
hibernates on the surface of the ground. In this 
country the favourite places for adders and ring snakes 
to choose for their winter quarters are holes in old 
trees, crevices in rocks, under masses of dead leaves in 
the woods, in fern or bracken, and, as we saw in the 
incident at Llanelly, in old quarries. A favourite 
retreat for adders when hibernating is amonest the 
roots of gorse. Where these bushes are large a space 
is formed round the larger roots by the action of the 
wind swaying the roots about, just as a hole is made 
with a crowbar. Into these holes both adders and 
ring snakes will withdraw on being disturbed, and 
will also hibernate in them. My Lees tells me that 
on one oecasion when uprooting vorse near a wood at 
Gwern Efa, Llantrisant (Glamorgan), for the purpose 
of clearing the land, a large number of ring snakes 
were found thus hibernating together. 
Frequently they are found entwined together in 
masses—for warmth, presumably. A correspondent 
of mine, to whom I owe the knowledge of many in- 
teresting adder incidents, writes me the following, 
1 Natural History (Vertebrates) of the British Islands. 
