NORTHWESTERN LAKES OF THE UNITED STATES. 
97 
LAKES IN WESTERN WASHINGTON. 
Table 8. — Lakes examined in western Washington. 
Almost two-thirds of the Crustacea were Cyclops viridis var. americanus, and 
43 per cent of them were found below 20 m. A few Epischura nevadensis var. 
columbise were found in this stratum, too, with the maximum number per cubic 
meter of water between 10 and 15 m. One-half of the Daphnia longispina var. 
hydlina and two-thirds of the Diaphanosoma leucktenbergianum were in the surface 
stratum. (See Table 12, p. 122.) 
The maximum number of nauplii per cubic meter of water occurred between 
15 and 20 m., or just below the thermocline; over half of the nauplii were in this 
stratum. 
The largest number of Rotifera per cubic meter of water was found between 
10 and 15 m. No rotifers were noted above 10 m. 
Anabsena was the predominant alga, with a few specimens of Microcystis and 
Aphanocapsa. Some diatoms belonging to the genera Cyclotella and Melosira were 
obtained in the 10-20 m. stratum, and some Melosira in the 20-25 m. stratum. 
LAKE CHAPLAIN, WASH. 
The thermocline in Lake Chaplain was between 3 and 5 m., the rapid drop in 
the temperature being due, in part at least, to the protection from the winds afforded 
by the surrounding forest. The maximum number of Crustacea per cubic meter 
of water was in the 0-3 m. stratum. All of the Epischura nevadensis, Diaphanosoma 
leuchtenbergianum, and Holopedium gibberum were confined to the surface stratum 
of the lake. No Crustacea were found below 9 m. (See Table 12, p. 123.) 
31177°— 23 i 
