ec 
<a 
ay 
— 438 
Among the latter are to be distinguished the crustacean parasites of the 
gills (tig. 10) or of the surface of the body, which may become so numerous. 
as to cause death (p. 446). Again there are various worm parasites (no species 
of fish is exempt from its share) which, however, appear rarely to cause any 
serious mortality. In many cases unripe stages of such worm parasites occur 
in fish, which only reach their full development in fish-eating birds, but one 
Fig. 10.—Ergasilus with egg-sacs from gills of sunfish. x 10. Achtheres from gills of catfish x 6, | 
species of such immature forms. occurring in the Pike, and possibly also-im 
some Salmonoids, is the larva of Bothriocephalus latus, the broad tape-worm of 
man. It is only found abundantly in those northern countries where fish are. 
eaten raw. Among the worm parasites may be mentioned certain thread-worms 
which (like the guinea worm) live in the skin of their host, and may often cause- 
serious abscesses in the fins of affected fish. Certain leeches (Piscicola) also may 
attach themselves to the skin and suck the blood of'their victims with fatal 
results. 
Obscure diseases of fish of epidemic character have not been properly 
investigated yet. Some are no doubt attributable to bacteria, others, like the 
salmon disease, to more visible fungus-growths such as Saprolegnia, but the 
subject of the wholesale dying-off of fish is one which requires further looking 
into. Reps 
PRESERVATION OF FISH. 
Should any reader of this report desire information as to any particular 
variety occurring in his locality, he is invited to send specimens to the author at. 
the University of Toronto. These ought to be suitably preserved before ship-. 
ment, either by putting on ice when caught and shipping promptly, or by immer- 
sion in a strong pickle formed of 14 Ibs. salt, 4 lb. saltpetre and 4 Ib. boracie acid 
to the gallon of water, or in strong spirits of wine. The preservative fluid 
used should be poured into the mouth, and if possible injected into the vent and 
through a small slit into the body-cavity. When alcohol is used as a preservative 
fluid it should be diluted with one-third water, so as to obviate shrinkage of the. 
tissues, and changed once or twice betore shipment. The label accompanying a. 
specimen should always give the exact place and date of capture, and any other 
information which occurs to the collector, such as colouration when fresh, which. 
is especially desirable if alcohol is used as the preservative fluid. | 
