THE YAN YEAN RESERVOIR, VICTORIA. 18 
the eolonies being more expanded than in the preceding month and the 
mucous investment practically invisible. — Mierasterias Hardyi, Eudorina 
elegans, and Botryococcus Braunii were all fairly abundant, and а few of the 
smaller Desmids were rare. Volvov aureus present in small quantity. 
Fragmentary filaments of small species of Zygnema and Spirogyra were not 
uncommon. Of the Diatoms, Melosira granulata was the most abundant, the 
filaments varying much in relative thickness. Navicula viridis was not at all 
uncommon, and next in order of frequency were Navicula bicapitata and 
Surirella robusta var. splendida. Dinobryon cylindricum, with its var. diver 
gens, had again appeared in fair abundance. 
Dee. 2nd, 1905.—Chlorophyceæ and Diatoms conspicuous, but Nauplii 
could almost be said to be dominant. Aicrasterias Hardyi and Volvow 
aureus were the most conspicuous of the Chlorophyceæ, and Melosira 
granulata much the most abundant of the Diatoms. —Sehróder's spiny 
variety of the latter species was greatly in evidence. Few small Desmids. 
Dinobryon cylindricum var. divergens present in great abundance. А feature 
of this December plankton was the presence of an immense multitude of long 
unicellular hairs of vegetable origin, and most probably brought into the 
lake by the heavy rains of the preceding month. It has not been possible to 
determine from which plant these hairs were derived. 
Jan. 6th, 1906.—The dominant constituents of the plankton were three 
species, one of each of the groups Bacillarieæ, Flagellata, and Chlorophyceæ. 
Melosira granulata and Dinobryon eylindrieum var. divergens were present in 
great abundance, and Pediastrum duplex var. reticulatum occurred in almost 
as great a profusion. Many of the filaments of Melosira granulata had 
developed auxospores. The most interesting Diatom was Zthizosolenia morsa, 
which was quite common.  Crucigenia and Oocystis make their first 
appearance after the colder weather. The smaller Desmids show signs of 
becoming quite common, but Micrasterias Hardyi was less abundant. 
Feb. 10th, 1906.—The dominant feature was the quantity of Melosira 
granulata, with a plentiful sprinkling of thick filaments derived from the 
auxospores of the preceding month. Dinobryon cylindricum var. divergens 
occurred in quantity, but the colonies were mostly broken up. Larger 
Desmids were common (e.g. Cosmarium Hardyi, Micrasterias Hardyi, 
Staurastrum longiradiatum, etc.), but there was no evident increase in the 
number of the smaller species. The most interesting species of the Chloro- 
рһусе were Lagerheimia splendens, which was distinetly rare, Kirchneriella 
lunaris, and Eudorina elegans. 
