
AILMENTS AND DISEASES 

epidemics in fishes and in immature and adult forms have been found in 
such numbers in the gills of young goldfishes as to cause the death of en- 
tire hatchings. These worms grow to such size that they force the 
opercule from the sides of the head and produce death from exhaustion 
and inability of the fishes to breathe. No preventive means or parasiticides 
have been devised to eradicate these destructive parasites, most of the 
species of which do not exceed 1 cm. in length, and many of them are 
much smaller. 
Hirupinip@ or Leecues. These parasites are divided into two 
groups, the Rhynchobdellide which pierce the tissues of their hosts by 
means of a fine protrusile stomodzum or proboscis, and the Guathobdellide 
which bite their prey by means of 
triangular horny jaws. They are carniv- 
orous oblong and generally depressed 
contractile worms, having the mouth 
encircled with a lip and a flat disc at 
the posterior end, both adopted to ad- 
here to other bodies and to serve as 
organs of locomotion. Leeches abound 
in both fresh and salt water and in 
tropical countries some forms live on 

FIG. 94. Piscicola funduli, the Carp-leech, at- av : 
tached to the head of a young Small-mouthed Black the land secreted pene leaves. Fishes, 
Bass. Slighty enlarged. frogs and turtles are most frequently 
attacked, but they also attach themselves to other animals which come to 
the water to drink. The larger blood-sucking forms are Hirudo and 
Macrobdella; and the true parasitic forms belong to Jchthyobdella, 
Cystobranchus and Clepsine which feed principally on fishes, 
and Nephilis and Aulastomus on snails and worms. The 
North American leeches which prey on freshwater fishes 
and amphibia are the species Piscicola funduli, known as the 
Carp-leech, Figs. 94 and 95, P. punclata, Actinobdella 
inequiannulata, Philobdella gracile, Clepsine elegans, and C. par- 
asitica. Young leeches infest the gills of fishes, especially FIG. 95. 
the fry, literally packing them solid, and gorge themselves pte eats 
with the blood, causing the death of their hosts. These 
epidemics sometimes occur with broods of goldfishes. The only remedy 
is to clean the tanks and destroy the aquatic plants. Cures of leech 
infested fishes have been made by the brackish water treatment and by 
injecting salt water into the gills. 
A very minute leech-like polyp Trichodina pediculus, Fig. 96, is 
usually parasitic on freshwater polyps but frequently changes to fishes as 

151 
