44 ° Macfarlane . — Observations on Pitchered 
ten pitchers which one may examine from their native haunts, 
a neat round hole is drilled in a swollen region of the tendril 
opposite the pitcher-bottom, while all pitchers, whether brought 
from their natural habitat or grown in conservatories at home, 
show the fusiform swelling. The explanation seems to be 
that this kind of ant, finding it could not reach the cool juice 
of the pitcher-cavity in the ordinary way without permanent 
risk to itself, has learned, on the physical principle that water 
will rise to its own level, to drill a hole in the tendril, and the 
liquid filtering up through the cells oozes out to regale the 
waiting ant. But the most interesting point about the 
condition is, that while plants grown in our conservatories 
are not troubled by the insect, the continued hypertrophy 
brought about by the constant liquid supply has so affected 
the constitution of the plant that the acquired character is 
hereditarily transmitted. Mr. Burbidge has informed me that 
the centre of the swelling is generally hollow, but both in 
material brought home by him and kindly placed at my 
disposal by the Director of the Royal Gardens, Kew, as well 
as in home-grown pitchers, if these are rather young, the tissue 
is solid though loose in texture, a breaking down of the cells 
only taking place in the older specimens. 
VI. General Morphology and Histology of the 
Flowers of Nepenthes. 
I have already stated (p. 416) that the Sarraceniaceae show 
many points of affinity in flower-structure with the Nepen- 
thaceae,and the affinity in pitcher-morphology has been already 
explained. Though somewhat of a digression, I may be 
allowed to discuss the systematic characters of the two orders, 
for I feel convinced that we have to deal with a group of plants 
that constitute a very natural alliance, though, owing to wide 
isolation in past ages, they have diverged in points which are 
of generic importance only. For comparison I subjoin the 
systematic characters of both orders in parallel columns. 
