EEE 
AILMENTS AND DISEASES 

extended like a porboscis. It is most frequently 
observed on fishes kept under unsanitary conditions 
or which have become exhausted from fright, trans- 
shipment or other disturbing causes. 
The following are nearly related forms. 
CHROMATOPHAGUS PARASITICUS. On the : 
bodies of freshwater fishes, very distinct milky-white ae ace 
spots develop, caused by these large infusoria lodg- enlarged. 
ing on, or in, the epidermis, which show a distinct rotating motion between 
the epidermic cells, Fig 109. These 
parasites are usually single, but some- 
times two or three are imbedded close 
together. Their shape is variable but 
most often oval with the longer diameter 
Ue 0.615 mm. and the shorter 0.408 mm. 
FIG: 169. Chomatiphapusparnaness, aninmenan be body as ‘enelosed ima sthunmelaete 
paraaite: Greatly enlirged. cuticle covered with fine cilia, the layer 
below finely granular, filled with a large number of contractile vacuoles of 
different size. They have a proboscis-like sucking tube. The presence of 
these parasites is manifested by the formation of cysts on the surface of 
the fishes, which enlarge until the skin and head are covered by funguslike 
postules in which the boring infusoria are encysted. Death results from 
exhaustion and the ravages produced by the parasites. A similar infusorian 
has been found in the blinded eye of a Telescope goldfish. 
Tetromitus nitscHEI. ‘This infusorian, Fig. 110, previously re- 
cognized as Contia necarix, is supposed to have only the Japanese Fringetai| 
goldfish as host, but a very similar species, Bodo necator, is very destructive 
to young trout in Europe, and the described form is 
probably a Japanese species of the same genus. This 
minute organism attaches itself to the surface and under 
the scales in vast numbers, often hundreds in a space as 
large as the head of a pin. Its presence is manifested by 
excessive mucous coating, red spots and ulcers. In the 
free-swimming stage it has a flattened appearance with 
cilia at one side by means of which it moves through the 
water until it comes in contact with its future host. 
When not checked this parasite may become so numerous FIG. 110, Tetromitus 
; ; nitschei, ( Contia necarix) 
as to cause the destruction of all the fishes in an aquarium. an Infusorian parasite. 
None of the other mentioned orders of Infusoria OreoTy Serer. 
are parasitic on fishes but a considerable number occur with other lower 
forms of aquatic fauna. 



