62 Proceedings of Societies. (January, 
forty inches in height, thirty-six feet in circumference at the base, and 
eleven feet at the top. They had probably taken seven years to grow 
to this size. On account of the dryness of the season, little activity 
was at first observed among the builders, but a shower of rain commenc- 
ing to fall, they immediately began to work. The mode of formation 
of the hills and galleries was described and illustrated by drawings and 
photographs. It was believed that no liquid was used in building the 
arches, but the pellets of which they were constructed were dovetailed 
into each other, and rain seemed necessary to cement the work. The 
greatest regularity in the galleries seemed to be north and south, while 
the long slope of the hills was towards the west. ‘This did not seem to 
be at all dependent upon the direction of the wind, but appeared as if 
the ants actually build with regard to the points of the compass. The 
doors of the galleries were not closed at night, as described by Huber. 
Peculiarities of structures made by ants of the same species in Dela-. 
ware County and at Rockland were described. 
Dr. Leidy spoke of the destruction of plants by ants in the neighbor- 
hood of their nests, either by the action of formic acid or by eating the 
roots. He had observed that a species of grass, Aristida, was exempt 
from this destruction. Whether the ants allowed it to remain for the 
purpose of strengthening their structure, or because they did not find it 
palatable, he could not decide. 
Mr. McCook stated that the ants observed by him extruded formic 
acid very vigorously, and he had observed yellow tracks on the trees, 
which might be owing to this cause. 
_ Dr. Koenig remarked that formic acid would produce a natural cement 
with the calcareous particles of the mounds. 
r. Chapman stated that the length of the cecum given off from the 
rectum of an ostrich recently examined by him was thirty-five inches. 
It was believed that the comparative length of this part of the intestine 
seemed to depend upon the nature and amount of the food. 
r. Meehan spoke of the Akebia quinata, an indigenous plant of 
Japan, where it bears fruit, although it had not been known to do so in 
this country until recently, when the fruit had been produced by a vine 
cultivated by Mr. Canby, of Wilmington, Del. 
Mr. Meehan also exhibited a specimen of rare fungus of the genus 
Phallus, which he had recently found on his grounds for the first time in ` 
seven years. Its peculiar odor attracted meat flies in considerable 
numbers. The bearing of the facts spoken of upon the question of 
insect agency in fertilization was dwelt upon. 
Dr. Leidy related his observations upon a species of Phallus, and 
mentioned the fact that insects carried the spores from. place to place. 
The power of insects to convey gangrene and other poisons was spoken 
of in this connection. 
The president announced that the Biological and Microscopical Section 
