Some Trematodes in South African Anura. 
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II. Some Trematodes in South African Anura, and the 
Eelationships and Distribution of their Hosts. 
It is a well-established fact that trematodes, as well as most parasitic 
worms, occur in fauna groups. If we investigate the trematodes in a par- 
ticular class of host in a defined zoo-geographical region, we will find that 
closely allied or similar trematodes probably live in the same class of host 
in a different zoo-geographical region. 
During the last four years I devoted a good deal of time to the examina- 
tion of frogs in search of trematodes. In view of the cosmopolitan occur- 
rence of the Anura throughout the Union, the present paper deals only with 
such trematodes as I have from time to time removed from frogs in the 
neighbourhood of the Cape Peninsula. A search for trematodes in frogs 
from the more inland districts, viz. Worcester, Middelburg (CP.), Molteno, 
and Dordrecht thus far yielded no results. The material, however, which I 
have collected clearly bear out the truth of the above-mentioned statement. 
Methods employed. — In looking for trematodes in frogs, I more or less 
followed the methods suggested by Johnston (14) and Looss (19). After 
inspecting the buccal cavity, the ventral body-wall was slit from vent to 
chin, the digestive tract laid open, and the whole length of the alimentary 
canal slit open, and the internal surface was examined with an eye-lens. 
The trematodes found in the body-cavity, gall-bladder, urinary bladder, 
lungs, etc., were immediately removed to glass dishes containing normal 
saline. Worms intended for whole mounts were placed in a drop of normal 
saline on a slide, and covered with a cover-glass or another slide according 
to the size of the worm. To prevent the cover-glass or the slide being 
washed away when the fixing fluid is added, it is necessary to put a small 
weight on the cover-glass or covering slide. The addition of a weight at 
the same time flattens out the object intended for a whole mount without 
appreciably changing its length. In the case of larger and stronger worms 
a good deal of pressure is often necessary to cause the worm to flatten out. 
In the case of small worms a small glass tube about 8 mm. in diameter and 
20 mm. long was used ; the pressure can then be regulated by the addition 
of a little mercury poured into the bottle. For larger and stronger worms 
small wooden cubes were placed on the upper slide and weights were then 
placed on these wooden blocks. In view of the action of fixatives on the 
metal weights, it is necessary to avoid such reactions by first using small 
wooden or glass cubes, and increase the pressure by adding small metal 
weights. The whole is now flooded with the fixing solution. 
I obtained the best results by using boiling or a hot saturated solution 
of corrosive sublimate in water with about 5 c.c. of 2 per cent, glacial acetic 
acid to every 100 c.c. After a few seconds the weights are lifted off for a 
