I2 SCIENTIFIC SURVEY OF TURNER'S LAKE 
over the surface are the micro-caddisfly larvae which clothe them- 
selves in mantles of silk and the delicate crystal spicules borrowed 
from the host. 
The dominant trees of the shores are the white and yellow birches, 
maples (Acer spicatum), and the arbor vitae; but scattered among 
them are balsam and spruce, poplar and mountain ash, with thickets 
of alders in the wet spots. Near the outlet and along the southwest 
bank, the withe-rod (Viburnum cassinoides) grows and with it the 
mountain holly (Nemopanthus mucronata.) 
The plants and animals named in the lists that follow are the com- 
mon obvious forms present in the lake and along its shores found 
during September, 1922. Collections made at other seasons of the 
year would doubtless augment the various lists, particularly that of 
aquatic insects. Enough evidence was collected however to show 
that the character of the water inhibits the growth of many organisms 
and that further study might throw some light on problems of soil 
and water preference. 
Considerable time was spent in taking soundings to determine the 
topography of the lake bottom; the results are shown on the accom- 
panying sketch map. Samples of water for analysis were taken 
with great care at the surface and at a depth of about fifty feet; the 
latter sample by means of a weighted container from which the 
stopper was removed and replaced by lines manipulated at the surface. 
We are greatly indebted to the various specialists who have identi- 
fied the materials collected and whose names accompany the lists; 
and to Mr. and Mrs. Ulysses S. Grant for many courtesies and much 
information concerning the island and its lake. 
PLANTS 
Determined by Dr. Homer D. House, N. Y. State Botanist; reviewed and 
checked by NatHanieL T. Kipper whose acquaintance with the flora of 
Isle-au-Haut is intimate. 
The majority of the plants listed below are aquatics or, in some 
cases, plants growing as aquatics that are ordinarily found in drier 
situations. No attempt was made to collect the species of the border- 
ing woods. 
Sparganium americanum Nutt. Bur-reed. This species and the 
next were found only in scattered patches in shallow water at the 
south end of the lake and infrequently along the west shore. It is 
rather common in low grounds from Nova Scotia and Ontario to 
Iowa, Oklahoma and South Carolina. 
