390 
NOTES OF A BOTANIST 
panduriform outline. Sometimes there is a pair of 
sacs, one on each side of the midrib, but in most 
cases the two sacs are confluent into one, which has 
a medial furrow along the upper side. 
I proceed to describe a few forms of sacs in 
various species of Tococa. In one species {T. diso- 
lenia, MSS. hb. 141 2) which grows by forest-streams 
entering the lower part of the Rio Negro, the 
leaves of each pair are very unequal, and the larger 
of the two (11 iDy 2>\ inches) is alone sacciferous. 
The axils of the inner pair of ribs are perforated, 
giving entrance to two tubes or fistulae — one on 
each side of the midrib — which conduct to a large 
basal sac, inhabited by small brownish ants, which 
pour out of the tubes and patter over the leaves to 
attack any animal that disturbs their domicile. 
In most species, however, the sac springs at once 
from the base of the inner ribs, through whose per- 
forated axils the ants have access to it without any 
intervening tubular way. 
T. btcllifei^a, Mart., grows in moist forests about 
the mouth of the Rio Negro, and is of humbler 
growth than the other species of the genus, reach- 
ing barely 5 feet ; but the berries are more juicy 
and better flavoured than in any other Tococa, 
although so scanty and perishable that they cannot 
possibly serve as food for ants except for a very 
short period, and can hardly have influenced them 
in the choice of an abode. The leaves are long- 
lanceolate, either subequal and then with a large 
fusiform sac at the base of each of the pair, or very 
unequal and then the smaller leaf esaccate. The 
sacs afford refuee to multitudes of minute reddish 
ants which are fragrant when crushed. . Most species 
