THE COMMON MOLE, MOLDWARP OR WANT 21 



the nest is often above the ground-level in the centre of a heap 

 of earth which is thrown up from converging runs (Figs. 7, 8, 

 and 9).^ Now, the easiest way to dispose of the earth when 

 the nest-cavity is being excavated is to push it upwards on to 



Fig. 9. — Section of Nest above Ground-level in Land liable to be Flooded. 



the surface, and in order to do this a tunnel must be made. 

 Fig. 10 shows the whole heap made entirely by this tunnel. 

 Fig. 1 1 illustrates a low fortress on boggy ground, the whole 

 heap being formed by a single tunnel (a) leading upwards from 

 the nest. This nest had seven outlets just below the soil. 

 There was no other tunnel or bolt-run." 



" When this superincumbent earth has reached an incon- 

 venient height another tunnel is made, sometimes from another 

 part of the nest-cavity (Figs. 3, 4 d, b), but more often side- 

 ways from the first upward tunnel." Meanwhile the Mole is 

 constantly making fresh runs from the fortress in various 

 directions in search of food. As these fresh runs grow in 

 length, the task of piling up the protective mound is lightened 

 by the excavations of new tunnels from runs near the edge 

 of the fortress, which usually lie above those leading from the 

 nest-cavity. 



The tunnels in the fortress serve two distinct purposes : — 

 {a) To eject earth from the nest-cavity and bolt-run. 



1 Key to Lettering on 18 Diagrams of Mole Excavations. 

 The same letters apply to all. 



Leg. = Lower circular gallery. 



u.c.g. = Upper circular gallery. 



T. = Turf. 



N. = Nest. 



Ni, N2, N3 = First, second, and third 

 nests. 



0.0. = Original outline of fortress. 



o.t. = Original tunnel formed by heap- 

 ing up the fortress. 



