363 
The lake waters in October-December contain (Table XIIL., 
Pl. XLVIIL.) but a fraction—from a third to a tenth—of the 
nitrogenous matter that is found in the channel. This is an 
index of the relative poverty of Quiver Lake waters when 
isolated as a separate unit of environment and dependent 
upon creek and spring waters, mainly of seepage origin, for its 
supply. This relative poverty, combined with the factors be- 
fore discussed, hes at the basis of the relatively small plankton 
production in this body of water in this year. 
1898. 
(Tables V., XIII.; Pl. XXIX., XLIX.) * 
There are 26 collections in this year at fortnightly inter- 
vals, with an average of 2.44 cm.’ as compared with 2.13 in the 
river, and a maximum of 42.14 on May 3 coincidently with the 
vernal maximum in the channel (Pl. XII.), which, however, 
falls 6.46 em.*, or 15 per cent., short of that in the lake. 
The parallelism in the movement of production noted to 
a varying extent in prior years may be traced also in 1898. The 
most striking coincidence is the agreement in the location and 
relative development of the vernal pulse, and further resem- 
blance may be seen in the June pulse and the December rise 
in production. The small quantities of plankton in the lake at 
other seasons and the fortnightly interval of collection render 
the correspondences less obvious though perhaps not less sig- 
nificant. 
During the low water of January and in the subsequent 
flood (Pl. XXIX.) there is little plankton in the lake (.02) as 
compared with the river (.45—see table between pp. 342 and 343), 
though an increase with a rise in levels and development of 
the reservoir function of the lake might have been expected. 
There is, therefore, no January-February rise in the lake cor- 
responding to that in the river unless the increase from .003 
Jan. 11 to .04 Jan. 25 be held to be significant. The February 
flood, which depletes the plankton of the channel, is accom- 
panied by arise to .58 on the 22d in the lake coincidently with 
