96 MIDLAND NATURALIST. 
appear in various places throughout the summer. Others never 
come till summer. Small pools and especially such as are dried up 
part of the year have been found to be most fruitful of the best forms 
as well as the greatest variety of forms. In large ponds and in 
streams of some size, or even backwaters of rivers water animals, 
crustacea, minnows destroy algae. Places even small that are 
permanently wet may have an abundance of material such as, 
Spirogyra, Mougeotia, CEdogonium, desmids free floating or as 
plankton, but oftener plants illustrating reproductive stages will be 
obtained from small bodies of water, streams or pools where the 
water has disappeared in summer or fall. Unicellular plants of 
Protococcoideae are usually found together. Luglena, Pandorina 
Eudorina, Gonium colonies are commonly found in summer as 
constituents of the green scum on the wallows in fields where pigs 
are kept. Wet places near troughs where cattle are watered are 
often covered with Augilena viridis. Water pools near barnyards 
when manure is present also contains Euglena and other Protococ- 
coid forms, especially when exposed to the hot sun. The Pandorina 
is usually found showing all stages of formation of smaller colonies 
within the old cells. 
ediastrum is usually found growing with Hydrodictyon and 
can be best obtained from the deposit falling from the floating 
plants to the bottom of the vessel in which they are kept. Often 
Pediastrum simplex is found with other unicellular forms or in 
common plankton floating on ponds. Desmids that secrete mucous 
are always found in shallow pools or sluggish streams either at 
the bottom when the water is cold, or rising to the surface when 
the water is warm and of lower specific gravity. Whenever such 
plankton is found in abundance which is rarely, conjugating forms 
will be present. The appearance of the plankton is that of a slimy 
mass often mucilaginous, but seldom or hardly ever stringy. 
Haematococcus grows only in rain water, and can usually be found 
in basins or other places where such water collects. It is ordinarily 
found only after rain. 
In collecting as well as growing algae great patience and per- 
sistence is necessary. It is always difficult to find the good stages 
of algae especially the rarer ones even when one has the best equip- 
-ment for collecting such. The microscope we have found most 
suitable is an instrument already described in these pages.* One 
* MIDLAND NATURALIST, Vol. I, No. 2, p. 53. 
