630 MINNESOTA BOTANICAL STUDIES. 
amygdalordes individuals is about 2%-3 inches in diameter at 
four inches from the ground, and 16 feetin height. The larg- 
est cottonwood, No. 5, shows a horizontal spread of its top of 
2% feet, while a willow (.S. amygdalozdes) near it spreads its 
branches 8 feet in a horizontal diameter. A number of trees 
have been marked and their study as well as that of the whole 
island is being continued. The willows are now so large that 
for some time a flock of English sparrows regularly roost in . 
them and they seem to prefer the part of the section that is 
flooded. 
ANIMAL LIFE OF THE ISLAND. 
Did the limits of this paper permit, an interesting chapter 
might be added under this heading. Crayfish, voles, mice, 
and muskrats burrow under and in the island, since the sum- 
mer of 1898, the cottontails resort to it, and in August of 1899 
some minks had made their home under the old ties, which 
once formed the engineer’s pontoon. Near the mink’s home a 
song-sparrow had hatched its young on a thistle bush. Some 
of the young trees on the West section have been infested with 
the spotted willow aphid, J/elanoxanthus salicits,* since the 
summer of 1899 and their secretions attract swarms of flies and 
wasps. That the frogs are there is self-evident, but I also 
captured a fine green tree-frog, and a bunch of prickly cater- 
pillars of the morning-cloak butterfly, Huvanessa antiopa, found 
their table spread on the willows. 
* Identified by Dr. Otto Lugger. 
