Flow to obtain tt. 
bo 
N 
is) 
eighths of an inch in diameter. The common one is A7gudus 
foliaceus. We have found them on gudgeon frequently, and also 
on trout and pike. They swim freely and adhere to their host by 
means of powerful suckers, and leave a bare patch wherever they 
have adhered, thus rendering the fish peculiarly liable to an attack 
of fungus. <A saline solution is the best remedy for this, and 
probably for most fresh water parasites. 
& 
oat 
oe \y) } 
Fig. 45. Argulus foliaceus, enlarged. 
Some of the worst parasites are the Entozoa or internal 
worms, which sometimes are found to be the cause of a considerable 
fatality amongst fish. We have taken a tape worm over two feet 
long out of a trout, as well as a dozen or so of small round- 
pointed worms, probably Azzularia. These may be introduced 
with food as cysts, and then develop, but as they are built in 
segments, and every joint or section may become another worm 
if detached, it is highly desirable that no domestic animal be 
drowned in a fish pond, or in a stream leading to one. Dogs are 
frequently troubled with worms, and the drowning of a dog might 
easily be the source of introduction, eventually causing serious 
disaster amongst the fish inhabiting the water. 
Every one probably has heard of the parasite commonly 
known by the name of “fungus,” or “salmon disease.” It is 
known to fish culturists as Saprolegnia ferax, but there are other 
species, probably, which will attack fish. There is another 
(Leptomitris clavatus) which attacks dead fish and decaying meat, 
but the Safrolegnia will grow on either the living or the dead. It 
grows in the water, and it can be grown in air in a hermetically 
