
AILMENTS AND DISEASES 

occurred. They are present in all bodies of water and a careful observa- 
tion of catches of freshwater fishes will almost always reveal some affected 
with the postules or tumors produced by these protozoan parasites. 



s 8 
oO u = 
© n 3 ° a = 5 ee n ! se a 
— ee 2 © ‘ 4 o1= B'S] 2 1 Ow 
1S) ~ <= n = vo i) oo vies bond las! 
@ Si Seine = S a jos 5 S| bo epee: 
ao o a] 2 fo ae, fe => 5 ey Mitel seul Weta | ee 
o oO She) pede tah | WS OH eee t= S 6S Oj] sis e 
mat tes sige | Pray batt Syed lost ES]| SPI Rea fceh tt) a! eile 5 oo 
o£ Host >| ule o o = de S15 9 ae) 
) a Bf feissunr=’ re 9 oO Ag; a9} | |=} (e' So ae yi es! ry, 
one olfelosl/ols SIS 5) 2ISSILS fle sle slg | Bs 
ne hee pe) boy to! |e tS) a oO wo Sl a oy) Ss a a= 
asics —Q S| en R= a re Hao ne st MH os oO 
& 1S) ea) = a P~ a ia ©} Yo re 
= ala Sy S os £213 Sine eee 
— S UO w iso = 
z sats ee A je |ala je = ae 
1 |Goldfish x x 
7 |Carp 531 5.0.45) (s-< x x x 
6 |Tench a ee x X x 
5 | Sunfish Gl Nee. x x 
4 [Stickleback XX XX 
4 |Minnow xa x =x 
3 | Perch x XX 
4 | Pike-perch xx | x x 
2°) iN Pike x x 
4 |Chub-sucker | xX |] xX x x 
1 |Mullet x 
2 |Gudgeon x x 
1 | Barbel Xx 
i Eel os 
2 |Catfish aOR 
2 Frog x x 
2 |Toad x Xx 
1 | Crayfish cs 
I Prawn = 
1 |Shrimp x 

Inrusorta. This section of the Protozoa includes orders which con- 
tain many parasitic genera. The countless host of Infusoria is divided 
into 3 classes, 13 orders and 306 genera; of which 286 recognized species 
occur in rivers and other freshwater, 76 species in pond water, 15 in marsh 
water, 4 in ditch water, 13 in bogs, 17 in standing and stagnant water, and 
I in spring water; while 80 species occur on or among aquatic plants, 35 
in and on entomostraca, 16 in and on frogs, toads and salamanders, 14 in 
molluscs, 5 in and on polyps and sponges, 4 in earthworms and tubifex, 
18 in aquatic insects, and 4 are parasitic in and on fishes. These are the 
following :— 
IcHTHYOPHTHIRID#. These infusoria are probably the most frequent 
and general forms of freshwater fish parasites. Small raised white spots de- 
velop on the skin, which increase to larger blotches, spread over the sides, 
head and fins, until the fish assumes the appearance of being dotted with 
white and covered with slime. These extend to the mouth and esophagus 
and enter the gills, when the fish wastes away from loss of appetite, difficulty 
156 
