188 PETCH : THE FUNGI 



hills are roughly conical, and the largest are only about six- 

 feet high. They are built of earth and grains of sand brought, 

 from the interior of the nest and cemented together by the 

 secretions of the termites. The upper part of the hill is con- 

 tinued into one or more conical hollow structures which may 

 be styled chimneys. The outline varies considerably : the 

 bill may slope gradually to the top of the chimney, it may 

 fork into several chimneys, or it may even have a solid apex, 

 and bear chimneys at the side. (PL V.). 



A section of the hill (PL VI.) shows that it consists of a 

 large number of separate cavities or chambers roughly oval 

 in shape, each 5-25 cms. in diameter and 5-15 cms. high. 

 The outer wall of the hill may be 20 cms. thick in large nests. 

 The floor of a chamber is more or less flat, and its arching walls 

 are smooth. The chambers are united to one another by 

 numerous passages, sometimes a centimetre in diameter, but 

 generally only large enough to permit the entrance of two 

 or three termites at once. Similar minute passages connect 

 the chambers laterally with the chimney shafts which 

 run down to the base of the nest. These shafts are at first 

 vertical, but when they reach the area occupied by the 

 chambers, i.e., the body of the hill, they pursue a tortuous 

 course between them : they do not open directly, or merge 

 intoj the chambers, but are connected with the latter by 

 nil tow horizontal side passages: they are circular or oval 

 in cross section with a diameter of 4-9 cms. (generally about 

 6 cms.). 



The chambers are not confined to the bill, but occupy also 

 the ground beneath and round it ; in fact the part of the nest 

 below ground is usually much more extensive than that 

 above. 



Each chamber is almost filled by a brown or grayish stn* 

 ture which resembles in forma coarse bath-sponge, and con- 

 of b labyrinth of galleries opening into one another by 

 perforations w all directions. It is built entirely <>f vegetable 



