4 
OF THE ALGAS GENERALLY. 
season after season, in the same situation; while other 
species, which were at one time just as abundant, have 
entirely vanished, without any apparent reason. Take, for 
example, Hydrodictyon utriculatum. It is quite astonish- 
ing in what abundance this species will suddenly fill some 
pond or ditch, at times almost obstructing the flow of 
water, only to disappear again after a while without 
leaving a trace behind. So that, if a person is anxious to 
gather a large number of specimens (for the sake, say, of 
making exchanges), he must be careful to do so while he 
has the opportunity, and not leave them to a future period, 
under the idea that they will await his convenience ; for 
he is likely enough in that case to deceive himself, and, on 
returning to the piece of water, to find only emptiness, 
where, the year before, there was superfluity. It is far 
better to secure the requisite number of examples on first 
coming across the species ; indeed, if necessary, the whole 
stock may be taken, as there is little likelihood of extir- 
pating any kind of Alga. 
What few implements are needed in the collection of 
Algse are neither complicated nor expensive. The following 
will be found useful : — 
1. A small iron or tin ladle, two inches across, fig. 7. 
About one-third of the circum- 
ference on the right hand side 
is provided with a number of 
teeth, three lines long, and bent 
inwards. A short hollow handle 
projects from one side of the 
ladle, whereby it may be at- 
tached to a walking-stick. 
This little instrument serves 
to fish out plants which lie be- 
yond arm’s length ; and the 
teeth may be usefully employed in entangling small species 
which occur on the surface of the water, such as Rivularise, 
Cylindrospermum, &c. 
Fig. 7. 
