73 
TV.—PARASITIC PROTOZOA IN SOUTH AFRICAN 
MARINE FISHES. 
By H. B. Fantuam, M.A., Cantab, D.Sc., Lond. 
Professor of Zoology, University College, Johannesburg. 
Various protozoal parasites may be found in fishes—some 
-on the outside of the bodies of the fish (e.g., on skin or gills), 
others in the digestive tract, and still others in the blood and 
‘various internal organs. 
As parasites essentially live at the expense of the living 
tissues of their hosts, it follows that parasites are harmful to 
their hosts in a greater or lesser degree, and—in the case of 
‘fish—detract from their economic food value. 
Through the courtesy of the Department of the Adminis- 
iratencurouei Professor |. D. Pi Gitchrist, F was enabled 
to search for protozoal parasites of fish at St. James’ Marine 
Laboratory neat Cape Town, during January and February, 
1918. I have much pleasure in tendering my hearty thanks 
to Dr. Gilchrist for his kindness to me and for the facilities for 
research which he so generously placed at my disposal. 
The Protozoa found may be grouped according to their 
‘systematic position, and briefly considered as under. 
Among the Sarcodina, parasitic Amoebae may be found in 
the digestive tracts of fishes, especially in the intestine. In 
the Bamboo fish, Box salpa, 1 found an Amoeba with nuclear 
structure closely resembling that of Amoeba lamax, which was 
probably not very harmful to the host. 
The Mastigophora include the important Sroup Or elie 
Flagellata. Parasitic forms such as Trypanosoma may occur 
in the blood, and other Flagellates such as Trypanoplasma 
may occur in the digestive tract. The Trypanosomes are 
transmitted from fish to fish by leeches. I have seen both 
blood Flagellates and intestinal Flagellates in South African 
marine fish. 
The Infusoria, which include the important group of the 
Ciliata, provide two genera of ectoparasites worthy of men- 
tion, namely, Ichthyophtlrnius and Trichodina. The former 
occurs on the skin of the host and, when present in large 
numbers, soon causes death among fish in aquaria, especially 
among fresh-water fish. The latter parasite, Tvichodina, lives 
on the gills of fish. In South Africa I have seen, in company 
with Professor Gilchrist, a Ciliate on the skin of certain fish, 
such as Klip fish (Clinus superciliosus and Clinus cottotdes), 
Harders (Mugil capito), Hottentots (Cantharus blochit) and 
Romans (Chrysophrys globiceps). The Ciliate, which is allied 
[C.P. 3—1918] 
